Pitching Repertoire of Justin Masterson

Justin Masterson is back where he started, signing with the Boston Red Sox as a free agent six years after his trade to the Cleveland Indians. Ian York studied the data and describes what to expect from Masterson when he takes the ball.

It may not be fair to focus on Masterson’s 2014 pitch repertoire, since injuries may have seriously affected his performance last year. Nevertheless, until it is clear that he has completely recovered, 2014 is the starting point and he wasn’t very good, posting an ERA+ of just 53. 

His most common pitches ‒ the sinker (“SI”) and four-seam fastball (“FF”) ‒ were hit hard when thrown in the strike zone, as shown by the large red bubbles. As the green contour maps show, his pitches didn’t even result in that many strikes, with the second-worst BB/9 among pitchers with at least 120 innings – far worse than his 2013 numbers (4.81 vs 3.54 in 2013). His velocity was also down from 2013, his fastball barely averaging 90-mph compared to his typical 92-93-mph in 2013.

Masterson has always had extreme LHB/RHB splits and while in 2014 RHB only hit a respectable .237/.359/.370/.729 against him, LHB hit a painful .320/.408/.502/.910:

(SI-Sinker, FF-Four-seam Fasball, SL-Slider)

However, there’s some room for optimism. Properly located, Masterson’s pitches were still difficult to hit hard. His sinker and his slider, even with reduced velocity, were especially challenging for RHB, and LHB had difficulty with them when located in the bottom third of the strike zone. His ground-ball percent remained very high at 58.2%, second in the majors for pitchers with at least 120 innings. And it’s important to keep in mind that not very long ago, in 2013, Masterson’s chart looked like this:


Despite a walk rate in 2013 that was high (72nd of 79 qualifying pitchers), the amount of blue in that chart shows a pitcher who was effectively fooling batters. If Masterson can recover a couple mph on his velocity and return to his usual locations in the strike zone, he can again be a useful pitcher in 2015.

The Red Sox presumptive starting rotation for 2015 has many question marks.  Three of the five pitchers had fairly poor years in 2014, with Kelly, Buchholz, and Masterson all posting significantly worse numbers in 2014 than in 2013.  Miley and Porcello have been fairly consistent over the past three years, but only at  league-average (career ERA+ of 104 and 101, respectively) levels. Boston fans have to hope that Buchholz, Masterson, and Kelly all revert to their 2013 form, that Porcello duplicates his more effective 2014 season, and Miley can deliver around 200 solid innings.  Even if we generously assume that each possibility, individually, has a 90% chance of coming true, that means there’s only about a slightly better than 50-50 chance of all of those working out.  However, if all these things do come true, and the Sox offense performs as expected, it could be a very good year in Boston.

Ian York visualizes baseball in a new, beautiful way, examining umpire strike zones, the repertoire of pitchers and the value of catcher framing.

Follow Ian on twitter @iayork. Follow us on twitter at @SOSHBaseball.

All data compiled from PITCHfx and Baseball-Reference.com.

About Ian York 208 Articles
Ian is an immunologist and virologist who lives in Atlanta with his wife and two sons. Most of his time is spent driving his kids to baseball and soccer games, during which he indoctrinates his children on the glories of Pedro Martinez, the many virtues of the Montreal Expos, and other important information.

Be the first to comment

Leave a Reply

Your email address will not be published.