January 22, 2022

Statistically Speaking: Craig Stammen’s Success Against American League Teams

As the season begins to wind down and the Washington Nationals gear up to face the Seattle Mariners later this week for their final interleague series of 2014, it is easy to use the matchup as a way to gauge how prepared the team is to face American League competition in the playoffs, as their chance for a postseason berth becomes more and more inevitable. While this sort of talk is pretty premature, it nonetheless gives us as good of a real time advance scouting report as we can get.

One of the more crucial components to the success of the season thus far and any extended playoff appearance is the bullpen. While many will focus on the performances of the ‘Big Three’ of the relief corps of Tyler Clippard, Rafael Soriano, and Drew Storen as key to the team’s success and potential long playoff run, it very well could be the play of oft-forgotten middle reliever Craig Stammen, who has been just as productive and impressive as the aforementioned trio, putting up a 3.56/3.06/3.41 ERA/FIP/xFIP pitcher ‘slash line’ in 65.2 innings in 2014, that sways a decision towards the win column.

However, Stammen’s fortunes against AL foes this season, especially the more recent 1.2 innings of 11-hit, seven-run ball against the Baltimore Orioles, have shown the sinkerballer to have some issues getting interleague outs; these difficulties getting outs could be limited to just the Orioles, or even this season.

For a better indication of whether or not Stammen has problems getting AL bats out, let’s turn to his career numbers (as a reliever) and calculate his fielding independent pitching (FIP) for each league and for home and away games to see if there is something to his issues when he faces the other league.

As a reminder, FIP is calculated using the formula:

 FIP = ((13*HR)+(3*(BB+HBP))-(2*K))/IP + constant

with the constant here set as the average of the three constants from 2012 to 2014—3.09—and is used to set league average FIP to league average ERA.

Here’s how Stammen’s FIP numbers look, with his xFIP as a comparison:

Away 3.39/5.25 3.55/3.90
Home 4.41/3.40 2.85/3.40
Total 3.73/4.24 3.18/3.63

Overall, Stammen has better success against NL foes, with the caveat that sample sizes play at least a small role in these results; the righthander has pitched 29.2 relief innings against the AL in his career, compared to 239.1 NL innings. With that said, his AL work does seem to take a dive during interleague competition at Nats Park, with his FIP a full run higher than expected (xFIP). Conversely, his FIP when pitching in AL stadiums is nearly two runs better than his xFIP predicts.

Let’s look at the main components of FIP and see if we can find the culprit behind Stammen’s issues with the AL, especially at Nats Park:

Away 14.20% 21.47% 0.00%
Home 22.75% 7.70% 8.33%
Total 18.86% 13.96% 4.55%
~ ~ ~ ~
Away 23.21% 8.42% 4.83%
Home 25.96% 7.14% 3.96%
Total 24.87% 7.71% 4.40%

Here, we find that home runs wreak havoc on Stammen’s success at Nats Park during a given interleague series, suffering an 8.33% home run per fly ball rate, twice of what’s seen during NL games at homes. In general, he also tends to strike out fewer AL batters, while walking more, with the exception being during home games, where he walks batters at the same rate as he does against NL foes.

Looking at some batted ball and strike statistics…

AL LD% GB% FB% F-Strike% SwStr%
Away 18.67% 41.00% 30.33% 60.34% 8.93%
Home 35.13% 45.35% 19.52% 60.06% 13.29%
Total 27.65% 43.37% 24.43% 60.18% 11.31%
~ ~ ~ ~
NL LD% GB% FB% F-Strike% SwStr%
Away 18.32% 48.70% 30.25% 61.89% 12.46%
Home 17.95% 49.55% 28.85% 63.30% 13.99%
Total 18.13% 49.04% 29.59% 62.80% 13.28%

…we find Stammen’s bowling ball sinker to be less sinker-ish against AL opponents with respect to his ground ball rate (GB%), but not egregiously so; given the same size disparities, these AL-NL numbers are all roughly in line with each other.

Again, we have one exception to this trend, with AL home line drive rates (LD%) double those seen during NL home games. We also find a slight discrepancy with Stammen’s first pitch strike rates (F-Strike%) between AL and NL games at Nats Park, but again, these aren’t significant departures from his usual averages.

With an inkling of what might be at the root of Stammen’s AL issues—harder hit balls, leading to more line drives and homers—let’s now look at his pitch repertoire and their respective pitch type linear weights per 100 pitches to see if there’s a particular offering that is getting hit harder than others. For these values, the more negative a number, the less successful Stammen has been with a pitch.

Again, sample size considerations with respect to how often he uses a given pitch must be mentioned, so attention must be paid to mostly his sinker (labeled a two-seamer, wFT/C), slider (wSL/C), and curveball offerings—a regular curve (wCU/C) and the more recently used spike curve (wKC/C)—with the righty using the sinker about 48 percent of the time, his slider 29 percent, and his curves collectively about 12 percent, with his other pitches making up the rest of his pitch counts.

Away 3.56 -5.67 3.24 2.05 -0.06 10.58
Home -9.39 -0.33 -0.63 -5.90 -11.58 n/a
Total -2.48 -2.47 1.03 -2.28 -7.26 10.58
Away -1.74 0.41 1.08 1.53 1.76 -2.27
Home 1.45 0.67 -0.04 -3.14 2.17 -0.74
Total -0.29 0.57 0.48 -0.75 1.99 -1.56

FA/C = four-seam fastball, CH/C = changeup, n/a = not applicable due to not using pitch

With linear weights, we find that most of the damage against Stammen versus the AL is done via the spike curve, with both fastballs also scoring poorly. In games against AL opponents at home, the picture becomes a little more concise, with the spike curve and the four-seam fastball being the biggest issues behind his poor showings. On the road against the AL, Stammen appears to fare much better with all of his offerings, with his usually wipeout slider being as such and even more so than when facing NL bats.

If Stammen does come in against the Mariners this coming weekend, it will be his first time facing the squad; while the first time through any order or facing any team can be particularly challenging, his history against AL shows that this test will be graded on a steeper curve. However, if he sticks to his bread and butter sinker/slider combo, his chances of maintaining his effective stead despite some less than encouraging outings in interleague play look to be high.

Looking to the postseason, this plan of attack should also treat him well; while these numbers may not necessarily reflect the current lineups of their given teams, they do point to Stammen being successful with a more simplified approach and perhaps not employing the curveball against AL opponents, if it can be at all avoided.

Data courtesy of FanGraphs and Brooks Baseball.


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 and a contributor at Camden Depot and Gammons Daily. 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.

About Stuart Wallace

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 Stu on Twitter @TClippardsSpecs.

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