January 25, 2022

Statistically Speaking: Is Drew Storen’s Rising Walk Rate A Concern?

Spring training stats aren’t everything — there are enough grains of salt to fill a dump truck when looking at the results from Grapefruit League games. With that in mind, the numbers that reliever Drew Storen has amassed thus far in 2014 are jarring, but for pitching coach Steve McCatty, there shouldn’t be much worry with respect to the clunker outings. To quote McCatty from the above linked Adam Kilgore article:

“Drew is Drew. At times, the ball is going to be elevated,” McCatty said. “We always work on getting it down. But I do see a good breaking ball.”

In a twist to the usual spring training sound bite ‘he’s working on things’, we find Storen, well, working on things; in particular, his location and his breaking ball (a slider). Fair enough. However, let’s take a look at Storen’s walk percentages from his breakout 2011 season to today, including his spring training rates:

Season BB%
2011 6.6%
2012 6.9%
2013_ST 7.7%
2013 7.1%
2014_ST 26.1%

Even while ignoring the eye-popping walk percentage for this spring (six walks in a little under six innings pitched), we find Storen’s regular season walks to be creeping up as time passes. Adding in the spring training rates for contrast and we find some discouraging trends to pair with the regular season numbers.

Let’s take a cue from McCatty and look at Storen’s walks by pitch type from 2011 onward, for granularity:

Storen Walk Rate

Storen’s changeup (CH) walk rate has gone up, which makes sense, given his increased use of the pitch; his bread-and-butter pitches—the sinker (SI) and slider (SL)  show a drop in walk percentage last season as compared to previous years, which is encouraging. However, there is a troubling hike in Storen’s walk percentage with his fourseamer in 2013, which he used 23 percent of the time.

So it appears a potential bugaboo for Storen is locating his fastball and with McCatty’s quote, it makes sense that Storen is missing up with the heater. Sadly, we don’t have PITCHf/x data for any of Storen’s 2014 spring outings, but we do have plenty of said data from the 2013 regular season. Assuming that Storen isn’t working on a new pitch and is actually improved, having more time to recover from early 2013 season health issues, let’s take a look the PITCHf/x data for each of Storen’s pitches on called balls. For the next four images, we are looking at a given pitch and a probability density map of the pitches that were called balls in reference to the strike zone. The lighter the color, the higher the probability a ball was actually called a ball.

First up, the four-seam fastball:


…and now the sinker:


…the slider:


…and finally, the changeup:


What’s interesting in these charts is the amount of light blue in the strike zone for each pitch, which are actual strikes that are being called balls. By the looks of it, Storen had a number of fastballs up in the zone called balls and a fair amount of changeups that were strikes incorrectly called balls. The trends are a little more egregious against right-handed batters, but is also seen to some extent against lefties.

The point of all of this? While you should never completely trust spring training numbers, some of the hike in walk rate seen from Storen might be more a result of strike zone interpretation more so than him losing command of his pitches. That being said, a careful eye should be kept on how well Storen commands his fastball up in the zone and his changeup down and out of the middle of the plate this coming season.

Statistically Speaking: Detwiler falls short

The decision to move lefty Ross Detwiler to the bullpen wasn’t one made lightly or with much joy by the Washington Nationals. Beset by injury and a 2014 spring training showing that found him working through a rough patch with respect to harnessing his secondary pitches (including a new one, a cut-fastball), inevitably, Detwiler got caught up in numbers games; games involving him being one of a number of capable pitchers vying for the fifth spot in the starting rotation and also those revolving around Det and his particular talents.

Talents that made him a first-rounder in the 2007 MLB Draft and led him to a breakout 1.6 fWAR 2012 season. Talents that have frustratingly been hampered by injury and a concomitant drop in fastball velocity, which, along with a lack of a reliable secondary pitch, has made Det a bit of a one-trick pony, something that is difficult to maintain in the starting rotation. As his reliever cohorts and former starting prospects Tyler Clippard, Rafael Soriano, and Craig Stammen can attest, the need for more than one effective pitch (and in reality, more than two) is just the tip of the iceberg when it comes to survival in the rotation.

Let’s look at what Detwiler did as a starter last season in comparison to starters with 150 or more innings pitched to see how far off he was in terms of providing effective innings as a back-of-the-rotation starter. We use the 150 inning criteria with the assumption that this number is roughly what is required from a number five starter.

First, the repertoire. Per FanGraphs and PITCHf/x data, Detwiler threw four pitches: a four-seam fastball (FA), a sinker (SI), a slider (SL), and a changeup (CH). Below, we see how often he threw those pitches in comparison to the NL average for pitchers with 150-plus innings, with standard deviations (SD) included to see how Detwiler slots:

NL Avg±SD 36±17.4 32.0±12.9 18.1±9.3 12.0±7.1
Detwiler 51.1 36.7 8.2 3.6

When summing up his fastball and sinker percentages into one value, we find that Detwiler threw hard stuff 87.8% of the time last year; when doing the same math for the average NL starters, we find the closest pitcher to that percentage is St. Louis Cardinal Shelby Miller, who threw some form of a fastball 73.6% of the time. Not surprisingly, Detwiler fell well below the average for secondary pitch percentages as well.

Now that the pitch frequency caveat has been beaten to death, let’s shift gears a bit and discuss how good a pitch was. Again turning to FanGraphs, we can use pitch type linear weights to help determine how successful a pitcher was with a given pitch. Below, we have Detwiler’s pitch type linear weights per 100 pitch basis (hence the ‘/C’ notation) for his 2013 offerings in comparison to the aforementioned NL starters with more than 150 IP:

NL Avg±SD 0.19±1.05 -0.32±0.39 0.06±2.07 0.04±1.53
Detwiler -0.12 -0.65 -3.55 -4.23

While me must be careful with how we interpret Detwiler’s offspeed results due to sample size and the potential for misclassification, we find that his fastballs (FA and SI) were both slightly below average, but still were within a standard deviation our NL averages. With the additional information the standard deviations give us, we find Det’s heaters were roughly average. We are also inclined to think that Detwiler’s secondary offerings were penalized somewhat by not only throwing so few of them, but also not being successful pitches when thrown in the form of high run expectancies. Simply put, even when he threw a secondary pitch, it more often than not led to a less than desirable outcome, be it a walk or a run scored.

So far, we have Detwiler relying heavily upon a pitch that was average and not throwing much else. Where did pitches end up once hit and was it any different than our average NL starter population?

NL Avg±SD 21.6±1.8 45.7±5.2 32.8±5.1 9.7±2.2
Detwiler 23.0 45.6 31.5 6.4

In general, Detwiler profiles as a starter here and more encouragingly, fares better than most in keeping homers at bay. The only red flag would be his line drive rate, which is borderline high.

Taking one step back in the process, let’s now look at where in the zone Detwiler pitches and how well hitters make contact, on average:

O-Swing% Z-Swing% O-Contact% Z-Contact% Zone% SwStr%
NL Avg±SD 30.5±2.7 62.5±2.7 63.3±6.3 88.2±2.5 49.5±3.5 9.3±1.7
Detwiler 32.2 66.9 75.6 92 50.7 6.6

For the above, ‘O-‘ stands for outside the zone, while ‘Z-‘ stands for inside the strike zone; SwStr% is swinging strike rate. By the looks of it, hitters swing a little more at pitches outside the zone on Detwiler. Contact rates against Detwiler are above the NL average in and out of the zone and at the same time, Detwiler does poorly with regards to getting hitters to swing and miss.

To paraphrase our findings, Detwiler is a one-pitch pitcher with said pitch being average in comparison to NL starters with at least 150 IP and his secondary offerings, while not seen often, are not up to par with other starters. With this, we also find Detwiler inducing higher than average amounts of contact, with below average swinging strike rates. While none of this completely dooms Detwiler and his chances of ever starting again, let’s discuss another piece of the starting pitcher puzzle that has escaped the lanky lefty, especially in 2013—success beyond the first time through an opponent’s batting order:

Time through order Detwiler wOBA NL Avg wOBA*
1st PA 0.302 0.309
2nd PA 0.393 0.317
3rd PA 0.413 0.336
4th+ PA 0** 0.310

*averages for all NL starters, no IP criteria used

**based on 2 PA

Using weighted on base average (wOBA) as our metric for the amount of offense against a pitcher, we find that NL starters tend to get hit a little more by the time they see a hitter a third time. Detwiler also displays this tendency, but in a more dramatic fashion, showing a 100 point swing in wOBA from the first and third plate appearance (PA) and a nearly 80 point swing in the third PA, in comparison to average NL starters. Here lies most of the damning evidence towards explaining sending Detwiler to the bullpen.

While these averages are from a 2013 season shortened by injury, the trends still stand; using Detwiler at his face value—a one-pitch pitcher—in shorter appearances more frequently lend him to be more productive and effective. Add to his difficulties in maintaining his health or consistent command of a second and third pitch and we see where the decision made shows the dedication that Nationals have in making the most of Ross Detwiler’s talents—talents that will serve him and the team well from the bullpen…for now.


Data courtesy of FanGraphs.com and Baseball-Reference.com


Stuart Wallace is a Contributor to District Sports Page. A neuroscientist by day, the Nevada native also moonlights as an Associate Managing Editor for Beyond the Box Score, stats intern at Baseball Prospectus, and a contributor at Camden Depot. A former pitcher, his brief career is sadly highlighted by giving up a lot of home runs to former National Johnny Estrada. You can follow him on Twitter @TClippardsSpecs.

Nats send Detwiler to pen, speaks to his long-term viability as starter

The Washington Nationals have decided to move Ross Detwiler to the bullpen. The oft-injured left-hander was reportedly “not happy” with the decision, and you could hardly blame him. This type of move, to a pitcher who should be in the prime of his career, signifies a team “giving up” on him as a starter and can [maybe unfairly] label him the rest of his career in the big leagues.

It’s no secret that relievers make less money in arbitration and free agency than starters, and this could potentially cripple Detwiler’s long-term earning potential.

But that’s a side effect really of the big picture. This move has been coming for a while.

Make no mistake, this decision isn’t about Matt Williams’ desire to have another lefty in the bullpen. This is a clear indication of how the organization feels about Detwiler’s long-term viability as a starting pitcher.

In his most complete season as a starter in the bigs, Detwiler went 10-8, 3.40, 1.223 in 2012, making 33 appearances and 27 starts at age 26. The baseball card stats showed promise that Detwiler could fulfill the potential everyone saw for him as a first round draft pick — No. 6 overall — in 2007.

But the underlying numbers then, as it’s always been for Detwiler, were underwhelming. The middling strikeout rate. The dip in velocity. An unusually low BABiP. An unnatural dip in line drive percentage, accompanied by an unexplainable rise in ground ball rate.

All those factors conspired against Detwiler when the GB% and LD% went back to career norms last season. Detwiler hadn’t taken a step up; he got lucky for a season. It happens. A lot.

Detwiler has two big things going against him as a starter. His inability to stay healthy (which as this point is as much of a “skill” as anything) and the fact that he only throws two pitches.

Fangraphs has Detwiler at 51.1 percent four-seam fastballs and 31.4 percent sinker, which is really just a different type of fastball. He threw 7.2 percent sliders and 5.7 percent changeups last season. That’s not the arsenal of a starting pitcher. In 2012, he threw the slider 12.6 percent. He’s all but abandoned it. Whether that’s his own doing of a team directive is an open question.

He was more hittable last season too. Contact against him both inside and outside the strike zone went up appreciably, which speaks to his lousy strikeout rate as his swinging strike rate plummeted from 7.2 percent in ’12 (not high to begin with) to a downright lousy 6.6 percent last season.

In the past three seasons, Detwiler’s four-seam has gone down from 93.0 in ’12 to 92.4 last season. The sinker lost 0.6 MPH as well. Is this due to the combination of injury he went through last season? Is it a compilation of injury throughout his career? Either way, one shouldn’t be losing velocity going from age 26 to age 27.

Which brings us to the injury problem. Detwiler has never had an arm injury, despite landing on the D.L. in the majors in both ’10 (hip–110 days) and ’13 (back, neck-116 days). Detwiler has always used a pronounced cross-body delivery, stepping towards the dugout instead of home plate and throwing across his body during his delivery. As an amateur, it allowed him a better whip motion and generated velocity for him.

Through the years, though, that same delivery has created a myriad of problems, as it’s very violent to several body parts, including the hip area. Accumulation of injury may have finally caught up with him, robbing him of just enough velocity to keep the action on his fastball less deceptive than his sinker.

A switch to the bullpen may allow him to generate that extra half-mile an hour that he needs to separate the fastball and sinker. Or, this may just be the first step in Detwiler fading to obscurity. Some starting pitchers (see Stammen, Craig) make the transition from starter to long reliever easily. Some not so much. It’s up to Detwiler at this point to salvage his baseball career.

But it’s clear that despite his previous amounts of success and his high draft pedigree, the Nats think (and probably rightfully so) that they can do better in the rotation.

Statistically Speaking: Defensive shift effect on Nationals hitters

Spring training so far has produced numerous surprises for the Washington Nationals, most of them coming from the mind of new manager Matt Williams. One of the more visible philosophical shifts has been his willingness to incorporate dramatic defensive shifts, which was on display last week against the Atlanta Braves. Add to this the Nationals naming Mark Weidemaier their defensive coordination advance coach and it’s plain to see the team and their new skipper will be shifting defensive paradigms in ways performed by only a few teams over the last few years, most frequently Pittsburgh, Tampa Bay, and Oakland.

Coinciding with this new approach to fielding has been the release of defensive shift data from last year, courtesy of Jeff Zimmerman at the Hardball Times. The data was broken down by: hitters hitting into a shift, and; by teams and how often they implement a shift. Batting average on in balls in play (BABIP) stats for each data type was provided and showed how the offensive environment changed.

Fellow Beyond the Box Score contributor Chris Teeter also provided a great piece discussing on how you can take these numbers and figure out how many runs are saved by a team’s defensive shift, which you can find here. I will leave it to the reader to peruse Teeter’s findings on how much the Nats shifted last season and how many runs the defense saved from doing it. For now, I’d like to shift attention to the hitter data, in particular, data from Nats hitters.

First baseman Adam LaRoche is a notorious pull hitter and, as such, has been on the receiving end of many defensive shifts. In 2013, he hit into a shift 161 times, the fourth most of any player in MLB. Taking the difference between his BABIP with a shift on and without a shift on and multiplying that difference by the number opportunities to hit into a shift, we can find out how many hits lost (or gained) when hitting into a shift.

With the number of hits, his batting event rate for 2013, and knowing the run value for each event—something we can find in The Book— we can figure out how many runs he (or any other hitter) gained or lost due to hitting into a shift.

…and that is exactly what I have done for Nats hitters, or at least most of them. In the table below, I collected shift hitting data for every Nat who a) had a least 150 plate appearances, b) is still on the team this spring, and c) hit into a shift at least once, per Zimmerman’s data.

Some descriptions of the ensuing madness:

- taking the difference in BABIP, with and without shifts, and multiplying it by the number of times a hitter hit into a shift (labeled Total below), I figured out how many hits a player gained or lost— this is labeled ‘Hits diff”.

- I then took ‘Hits diff’ data and multiplied it by batting event rates, which are the frequencies at which each hitter hit a single, double, or triple; since home runs aren’t considered balls in play, they were not included in the calculation.

- each ‘Hits diff’ by batting event rate frequency was then multiplied by its proper run value (0.474 for 1B, .764 for 2B, and 1.063 for 3B) and then summed; this summary value is labeled ‘Runs’ in the table below:

Player Bats Total BABIP w/ Shift On BABIP w/o Shift On BABIP diff Hits diff Runs
Adam LaRoche L 161 0.286 0.272 -0.014 2.254 (+) +0.363
Bryce Harper L 9 0.444 0.303 -0.141 1.269 (+) +0.607
Danny Espinosa B 4 0.000 0.184 0.184 0.736 -0.593
Denard Span L 4 0.250 0.303 0.053 0.212 -0.350
Ryan Zimmerman R 1 0.000 0.318 0.318 0.318 -0.347
Ian Desmond R 1 0.000 0.337 0.337 0.337 -0.395
Tyler Moore R 1 0.000 0.313 0.313 0.313 -0.360
Wilson Ramos R 1 0.000 0.274 0.274 0.274 -0.182

An interesting quirk in this data is the fact that both LaRoche and Bryce Harper hit better with a shift on and have contributed additional runs with a shift employed against them. Overall, the Nats don’t suffer much due to defensive shifts—they lose 2.23 runs, but gain 0.970 of it back from LaRoche and Harper.

However, we must take into account the scant number of times the rest of the team have hit into a shift — 21 at bats is a very tiny sample in which to make any grandiose statements arising from the results of the sample. Just as a means of comparison, Phillies first baseman Ryan Howard suffered the greatest against the shift in 2013, hitting into one 149 times, ‘losing’ 28.45 hits and 8.63 runs as a result.

Of course this data will change and evolve in 2014; it will be interesting to see if, like the Nats themselves, other teams begin to shift more frequently and aggressively. It will also be interesting to see how hitters like the aforementioned Rendon and Werth will respond to possible shifts, given their lack exposure to them, and if Harper and LaRoche can continue to take advantage of these shifts and hit ‘em where they ain’t.


Data courtesy of FanGraphs, unless otherwise noted.

Stuart Wallace is a Contributor to District Sports Page. A neuroscientist by day, the Nevada native also moonlights as an Associate Managing Editor for Beyond the Box Score, stats intern at Baseball Prospectus, and a contributor at Camden Depot. A former pitcher, his brief career is sadly highlighted by giving up a lot of home runs to former National Johnny Estrada. You can follow him on Twitter @TClippardsSpecs.

Statistically Speaking: Retreating velocity

Tyler Clippard earned 30th save - Chicago Cubs v. Washington Nationals, 9/3/2012. (Cheryl Nichols/District Sports Page)

Tyler Clippard pitches in Sept. 2012. (Cheryl Nichols/District Sports Page)

Imitation is the most sincerest form of flattery, they say. For this week’s Statistically Speaking piece, I am going to take my cues from Doug Thorburn over at Baseball Prospectus and his latest Raising Aces article. Not only am I batting my statistical eyelashes at Doug, but I also hope that for those who aren’t already, you take a look at what the folks at BP are doing. If you’re still timidly dipping your toe in the sabermetric/advanced stat water, BP is as warm as they come.

Back to Thorburn’s Under the Gun 2.0 article and the premise. Briefly, velocity is king when it comes to pitching. Not only does elite, or at least above average velocity help in getting hitters out all unto itself, but it also sets up other pitches, adding to (or detracts from) the effectiveness of a pitcher’s other pitches.

A good fastball, both in terms of velocity and location, is what makes Stephen Strasburg’s changeup, Gio Gonzalez’s curveball, and Tyler Clippard’s changeup all the more devastating. Take away fastball velocity and things become a little more precarious. With less velocity on the fastball comes less disparity in the velocity between it and other pitches, which can allow batters better identify and adjust to an offspeed and breaking pitch, as they are no longer concerned about not being able to catch up to the fastball, should they guess incorrectly.

Also, with less fastball velocity comes more focus from the pitcher on hitting particular spots in the strike zone, especially, the corners of the plate. Essentially, less velocity can mean fewer pitches to throw and a smaller strike zone to throw at, since any mistakes with the heater over the middle of the plate are now home runs, instead of foul tips or lazy popups that can come with good velocity.

With that in mind, let’s take a look at members of the Nats staff that might be losing a little giddyup on their heater and might be victim of retreating velocity. First, let’s discuss how we came to our sample of hurlers, courtesy of Thorburn:

We are looking at the three-year period from 2011-13. Each of the pitchers in the charts below suffered at least a half-mph drop from each of the previous two seasons to 2013, as well as the loss of a full tick from at least one of the two years under the microscope to 2013. In order to qualify, a pitcher had to throw at least 500 pitches that qualified as fastballs or sinkers in each of the past three seasons. The numbers in the charts were calculated based on a weighted average of the pitch-speeds of four-seam fastballs and sinkers in each season.

Using this as a starting point, I did a little more tweaking of the selection criteria, so it wasn’t as strict. Looking at drops in fastball velocity, I only looked at whether a pitcher had at least a half mile per hour drop between the 2012 and 2013 seasons and if they had a full mile per hour drop in velocity between 2011 and 2013. Instead of a 500 pitch criteria, I used 450 pitches of any type of fastball in all of the three seasons considered.

Also, with regards to ‘fastballs’, I counted four-seam and two-seam fastballs as well as sinkers as ‘fastballs’. All pitch data was courtesy of the FanGraphs PITCHf/x cards from all Nats pitchers between 2011 and 2013. Weighted averages for all three fastball types were then collected across the three seasons.

With those particulars out of the way, let’s look at our qualifying pitchers and their results:

2013 FB Velo, avg. 2012 FB Velo, avg. 2011 FB Velo, avg. Velo difference (MPH), 2012-13 Velo difference (MPH), 2011-13
Gio Gonzalez 92.49 92.95 92.38 0.46 -0.11
Jordan Zimmermann 93.91 93.80 93.30 -0.11 -0.61
Ross Detwiler 92.07 92.67 92.00 0.60 -0.07
Ross Ohlendorf 92.50 90.72 91.24 -1.78 -1.26
Ryan Mattheus 92.70 93.28 93.78 0.58 1.08
Stephen Strasburg 95.22 95.65 95.74 0.43 0.52
Tyler Clippard 92.00 92.70 92.60 0.70 0.60

Overall, we have three pitchers who might be at risk for decreases in performance due to decreased fastball velocities—Ross Detwiler, Ryan Mattheus, and Tyler Clippard. Mattheus in particular is in more of a danger zone, suffering both a half mile drop in velocity between 2012 and 2013 and a full mile drop in velocity from 2011 to last season. Also of interest are the pitchers who have added velocity over time (results that are a negative number), with Ross Ohlendorf leading the pack, with a nearly two mile hike in fastball velocity over the last two seasons.

What could this mean for 2014? It could lend pause to a big bounce back season from the likes of Mattheus, but it could also be statistical noise, brought on by the reality that both Detwiler and Mattheus suffered significant injuries over the last year-plus and these velocity disparities could just be a ramification of those setbacks. Given Mattheus’ results have been a double whammy for velocity declines, it could lend credence to larger issues with a return to his previous productivity in 2014.

For Clippard, who has been very resilient over his career, the velocity drop could also be concerning. However, further improvements to his command of the fastball and changeup, as well as the incorporation of an additional pitch could help offset any significant issues with declining velocity. The news of Clip toying with a split-finger fastball late last season while additionally slowly incorporating his breaking ball into his repertoire last year point to him adding to his fastball/changeup combo, possibly in order to combat some of the effects of dwindling miles per hour on his trademark up-in-the-zone heater.

With a 2013 cumulative 16.4 (FanGraphs) wins above replacement amongst the staff as evidence, it’s clear that the Nationals are heavily reliant upon their pitching to lead them to victory. While there’s more to successful pitching than just displaying a ‘grip it and rip it’ attitude, the data as portrayed does show there being a delicate balance between fastball velocity and the overall value of a pitcher’s repertoire. It also shows the possibility of the previously rock solid Nats bullpen showing signs of wear and tear as they gear up for the 2014 season.

Statistically Speaking: Should Espinosa ditch switch hitting?

[Eds. Note: “Statistically Speaking” is our new weekly feature, where we’ll delve into a particular aspect of the Nationals and really break down the essence of the issue in terms of statistical data. Typically, this will be performed by columnist Stuart Wallace (find his bio below), but Dave Nichols will pop up occasionally as well.]

The 2014 season is one that looms large in the career of Danny Espinosa. After a much-maligned 2013 season due to injury and ineffectiveness, Espinosa comes into the spring with a lot riding on him making strides offensively and coming north with the squad. Part of this success hinges on his ability to switch-hit and provide some pop from both sides of the plate, something he showed glimpses of in the 2010 through 2012 seasons, but remained elusive throughout a lost 2013, a season highlighted by a disappointing .206 weighted on base average (wOBA) and a -0.6 fWAR in 44 games with the Nationals.

Struggles notwithstanding, this projected pop is predicated upon the work that needs to be put in to maintain two swings and have them both remain synchronous throughout the year, impervious to extensive stretches of slumps and disharmony between both body and mind.

With his poor showing in 2013 came a number of suggestions as to how to ‘fix’ Espinosa and his swings, most leaning heavily upon the idea that he should scrap swings from one side of the plate and focus all of his efforts into one side of the plate, with the idea that the physical and mental demands of maintaining both swings would be drastically reduced by focusing on just one.

Adding to the melange of suggestions pointing to this quick fix was the success of Boston Red Sox outfielder Shane Victorino had late in 2013 with jettisoning hitting from the left, due to injury concerns. Victorino enjoyed what seemed to be immediate success, being able to hit for both average and power focusing solely on batting from the right. While Victorino appears to be working towards a return to switch-hitting status full-time, his brief dalliance with simplifying matters was nonetheless a successful one.

Is it one that might help Espinosa regain some offensive value to go with his elite defensive prowess?

Let’s have a look at Espinosa’s career left-right splits as a hitter:












vs. LHP











vs. RHP











Not surprisingly, Espinosa has better success at the plate as a righthander, facing left-handed pitching, hitting 50 points better from the right, as measured by wOBA, than the left. Surprisingly, Espi doesn’t appear to have any egregious differences in line drive rate (LD%), or even home run per fly ball (HR/FB) or strikeout (K%) rates between hitting sides.

In many respects, it appears that Espinosa has a touch more luck facing lefties, as his above-.300 batting average on balls in play (BABIP) as a righty hitter points to; with no real differences in the types of batted ball between the splits, his career numbers lean towards balls finding a hole from the right more frequently than they do batting lefty. While minute, Espinosa does appear to display slightly more plate discipline, with fewer strikeouts and more walks (BB%) as a righty.

Let’s delve a little deeper into Espinosa’s plate discipline over his career, in the form of whiffs per swing zone profiles, courtesy of Brooks Baseball. First, we look at his whiffs per swing rates as a left-handed batter; from left to right, we find his rates against hard pitches, breaking pitches, and offspeed pitches:

Espi as lefty batter

…and as a right-handed batter:

Espi as righty batter

With the simple evaluation of how well he makes contact across pitch types and bat handedness, we find additional confirmation of Espinosa faring better as a righty, facing left-handed pitching. In general, we find Espi less susceptible to fastballs high in the zone and breaking balls in general as a righty, with occasional problems with offspeed stuff up in the zone. Nonetheless, there are fewer red boxes as a righty, indicating fewer whiffs and, in general, better ability to make contact.

As shown, Espinosa’s success does appear to lean towards his ability to make more frequent contact as a righty, despite most of the stats not showing large platoon splits. However, the reality is that switch hitting is altogether a different beast and isn’t just an amalgamation of left and right swings. As mentioned in a recent article on the subject in Baseball Prospectus, there will typically be an adjustment period for most, if not all, switch-hitters to undergo in order to successfully transition back to hitting from one side of the plate, with many physical and psychological hurdles to overcome in the process.

Briefly, it wouldn’t be terribly fair or feasible to force a transition of this magnitude, after many years of training and success as a switch hitter, upon a hitter mid-career; the odds are against this great of a change bringing long-term success.

What does the future hold for Espinosa with regards to his switch-hitting status? A quick perusal of The Book finds that it takes roughly 600 plate appearances (PA) against left-handed pitchers to really determine a switch-hitter’s platoon skill, which Espinosa is a little over 200 PA’s short of achieving. We also find that switch hitters tend to display smaller differences in performance with regards to left-right splits than their lefty or righty-only counterparts. With a little mathematical help and some quick calculations, we can find out what Espinosa’s future could hold for him in regards to wOBA as a switch hitter.

Taking his wOBA left-right split over his career and regressing his output, using National League switch hitter averages, we can see how, despite his woes at the moment keeping things together from both sides of the plate, Espinosa’s ability to not suffer too greatly from platoon splits should endure.

Math ahead – for those averse, you can skip this part.

First, let’s look at Espi’s career wOBA, career wOBA from the left and right, the raw difference between these two, and the percent difference between Espinosa’s career left-right wOBA:

Career wOBA


Diff L/R wOBA


Pct wOBA diff


Overall, roughly 16 percent of Espinosa’s observed performance is in his wOBA splits. Let’s now take into consideration that Espi has yet to reach that magic 600 PA against left-handed pitchers threshold, so let’s estimate his platoon skill at 600 PA, using NL-average wOBA split for switch hitters for 2013, which I have calculated at 0.971 percent:

Estimated platoon skill = (.1633*394 PA + .0097*600 PA)/(394 PA + 600 PA) = 7.1%

Taking this 7.1 percent and centering it, we can now take Espinosa’s estimated 2014 wOBA—here, I am using ZiPS’ .287 wOBA— and look at how much difference will lie between his wOBA splits, which come to .290 against lefties and .284 against righties. Not a tremendous uptick or downtick, which is typical of switch hitters.

What if Espinosa ditched batting left-handed and went with just hitting righty? Given there are statistical differences regarding platoon splits for lefty/righty only hitters compared to switch hitters, we will have to make some assumptions to do a similar regression to the one above; the first assumption is that Espinosa, the right-handed hitter, will hit at a NL-average level with respect to his wOBA splits. Again looking to The Book for guidance, we will regress righty platoon skills against 2200 PA against left-handed pitchers in place of the 600 PA used for switch hitters.

For NL righty hitters in 2013, their wOBA splits are as follows:

2013 avg wOBA, NL RHH


Diff L/R wOBA


Pct wOBA diff


Taking these numbers and regressing them against the 2200 PA against LHP threshold for Espinosa, we get the following:

Estimated platoon skill = (.1633*394 PA + .0703*2200 PA)/(394 PA + 2200 PA) = 8.4%

Again centering this value and applying it to Espinosa’s 2014 ZiPS projection .287 wOBA, we find that he forecasts to a wOBA against left-handed pitching as a pure righty hitter at .289, with a .285 wOBA against righty pitchers as a same side hitter.

Overall, we find that Espinosa as purely a right-handed hitter doesn’t project to be much better than what he does as a switch hitter, with wOBA as our guide. Given these calculations and the multitude of mechanical and mental changes to his hitting approach that would be required to make a transition to being only a right-handed hitter after many years and swings as a switch hitter, which appears to be his stronger side given his career numbers, we find that Espinosa is best left as a switch hitter.

While it is attractive to look at the raw left-right splits that Espinosa has displayed over his career, when taking onto consideration plate appearances and assuming league average results throughout the reversion from switch hitter to a righty-only hitter, we find that Espinosa’s best bet to regain value from an offensive standpoint is to stay the course.

***All data courtesy of Baseball-Reference and FanGraphs, unless otherwise noted.

Stuart Wallace is a Contributor to District Sports Page. A neuroscientist by day, the Nevada native also moonlights as an Associate Managing Editor for Beyond the Box Score, stats intern at Baseball Prospectus, and a contributor at Camden Depot. A former pitcher, his brief career is sadly highlighted by giving up a lot of home runs to former National Johnny Estrada. You can follow him on Twitter @TClippardsSpecs.

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