Justin Masterson is a major league pitcher. According to Fangraphs data, his 180 innings for Cleveland last year tied him with Fausto as the most valuable contributor (2.7 WAR) on the pitching staff. Justin handles himself very well against major league right-handed hitters (8.8 K/9, 2.9 BB/9, 2.96 FIP in 2010). What Justin does not do, and what we all know about him already, is that he does not pitch nearly as effectively against left handed hitters (5.4 K/9, 4.3 BB/9, 4.78 FIP in 2010). It is difficult to survive as a starter with those kinds of splits, particularly pitching in a division where so many of our opponents top hitters are lefties (e.g. Mauer, Morneau, Dunn, Martinez). Masterson actually faced more left-handers last season than right-handers, 443 to 359.
Masterson regularly uses three different pitches: a four-seam fastball, two-seam fastball, and a slider. All of these pitches are, to a varying degree, effective. But there is a fourth pitch Masterson used last year, a changeup, and it is telling to see how and when he used this pitch. Masterson's first two starts of the 2010 campaign were, by any reasonable standard, very effective; 11 IP, 3 ER, 14K, 2BB. But with his third start, Masterson began experimenting with his changeup, particularly against left-handers. In the first 6 starts Masterson used the changeup, he only threw it to a right-handed hitter once. According to fangraphs pitch f/x data, as a starter throughout the season, Masterson used his changeup 4x as often against lefties than righties (48 vs. 12). Even facing more lefties than righties in 2010 (55/45), this is a striking difference. Especially because his changeup did not work.
In addition to not beginning the year throwing the change, Masterson essentially abandoned it by mid-July. The two stretches he used it most frequently span from April 20-May 24 (0-4, 7.25 ERA) and June 15-July 11 (1-3, 6.38 ERA), and both were horrible. In his starts outside of those time spans Masterson had a 3.38 ERA. Masterson's changeup does not have to be an effective out-pitch. If he is going to use it, though, it has to be able to make his other pitches better. Right now it very clearly is not doing that. In 2010, if you saw more than a few changeups from Masterson on the mound, chances are you were watching a bad game.
Masterson's poor results with the changeup raises the question of whether he needs the pitch at all. The problem, again, is that even if you filter out his changeups, Masterson is not effective against lefties. Masterson's slider, which is a good pitch against right-handers, is not as effective against lefties. The percentage of swinging strikes Masterson gets on his slider against righties (16.5%, an excellent number) dips considerably against lefties (11.8%) who have a much better view of the pitch coming because of Masterson's delivery.
Even if Masterson does not improve his changeup, one area of work that could increase his effectiveness is improved control. Gamescore is a crude metric, but in starts where Masterson threw more than 60% strikes his average gamescore was 51. In starts where he threw 60% or fewer strikes, his average gamescore was 37. But again, Masterson's control problems are much more dramatic against lefties (10.4% BB-rate) than righties (7.5%). Masterson's seeming hesitation with his "stuff" results in an unwillingness to pound the strike zone. Reflective of Masterson's control issues is his heavy reliance on his fastball with 3 balls (~94%). With two strikes, in contrast, Masterson increases the usage of his slider (from ~20% overall to more than 30%), working it as an effective out-pitch. But once again, Masterson hesitates to use it against left-handers.
I don't really know what to say about Masterson. I am still optimistic about his future, but he has to do better against lefties one way or another. The changeup, while still a possibility for the future, didn't work in 2010. It seems the Indians and Justin have to decide whether to go ahead and try to sharpen his change, find a different pitch that might disrupt the timing/eye level of left-handers, or abandon the project altogether and accept that Justin is a fastball-slider pitcher, period. The latter seems to have the highest probability of bringing with it a shift back to the bullpen.
- Work ahead in the count more often (first strike% >55)
- Either abandon the changeup or make it a positve pitch (usage rate ~0% or pitch value close to 0)
- Narrower peripheral splits between RHB and LHB (BB <3/9IP, K >6/9IP vs. lefties)
- More groundballs (>60%)
- More strikeouts (>20%)