June 21, 2018

Statistically Speaking: Aaron Barrett’s Third Pitch

In a continuation of my personal infatuation with the members of the Washington Nationals bullpen, this week’s Statistically Speaking looks at the contributions and success of one of the non ‘Big Three’ relievers, rookie Aaron Barrett. A 2.79/2.52/3.09 ERA/FIP/xFIP pitching slash line to go along with a 0.6 fWAR has all been made possible for the righthander due to a solid fastball-slider combination, with the breaking pitch being particularly tough on hitters, as alluded to by Barrett’s 28.7% strikeout rate.

Not immune to many of the foils of a rookie season, Barrett’s 2014 has been bisected by a brief return to the minors—the entire month of August was spent at Class AAA Syracuse—which saw him work not only on a small mechanical hiccup, but also on a third pitch, a circle changeup.

While he had already flashed the pitch in his pre-demotion innings with the Nationals, throwing it five times, or 0.88% of his pitches, it wasn’t until September that the pitch became more than a fleeting thought.

Barrett has only thrown the pitch seven times in his five post-call up innings, but here, it accounts for nearly ten percent (9.72%) of his pitches, showing his willingness to throw the third offering frequently. The tiny smattering of changeups Barrett has thrown don’t really give us enough information to determine whether it’s a good pitch or one that has been greatly improved by his time in Syracuse, but we can look at how he has used the pitch and see if it has possibly made his other pitches better. First, let look at his pitch type linear weights per 100 pitches thrown for each offering for the season:

Year wFA/C wFT/C wFC/C wSL/C wCH/C
2014 0.93 -0.03 1.09 1.91 -11.34

While Barrett’s two fastballs—a two-seam/sinker and four-seam—are joined by the cutter (FC/C) in this table, this is simply a matter of the differences between how various sourced classify a given pitch (hence the removal of the curveball data, as he doesn’t throw one); overall, the trend is that his fastball is above average, with the slider showing itself to be a great pitch as well. The changeup (CH/C)—all 12 of them—shows itself to be a subpar pitch, when extrapolating out of the results to 100 pitches. However, looking at the offering split pre/post demotion, one improvement does come up: On the left, we see the ‘old’ changeup, with the new and improved cambio on the right; here, we find Barrett’s command of the pitch has the makings of becoming improved, with fewer of them hanging up over the plate and his ability to bury the pitch down in the zone to getting better. Again, this is such a small sample, so caveat emptor for the moment.

However, it isn’t necessarily what the pitch does, but what throwing a pitch does to the next pitch, with a batter now concerned not only with the mid-90’s fastballs and hard slider, but also a change of speed pitch with tailing action. It is here that would would potentially see whether the pitch is evolving and whether the changeup has life in it. With this in mind, let’s look at Barrett’s other pitches—fastballs and slider—but this time, looking at the differences (if any) between what pitches batters swung at in the zone location-wise before and after the improved and more frequently used changeup: While the trend is faint and again limited by sample size, we do see a slight opening up of the lower right outside corner for Barrett, more than likely due to locating his slider down and away to righties. More data is needed to be certain whether it is truly the changeup that is causing this trend.

Looking at his other pitches pre/post changeup improvement with regards to their outcomes finds Barrett’s other pitches to be a little tougher to make contact with, going from an 8.3% to an 11.9% whiff rate on his fastballs and slider. Overall, this trend is small, but is encouraging; the data and sample size aren’t much, but they do show the time Barrett has taken to refine the pitch and to begin to use it is starting to pay dividends, albeit in an indirect fashion.

Should he continue to work on the pitch while maintaining his already potent fastball-slider combo, Barrett will continue to give hitters fits in the late innings, giving the Nationals yet another elite arm to consider in late game, high leverage situations.

Data courtesy of FanGraphs, Brooks Baseball, and Baseball Savant.

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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