Red Sox Pitcher Joe Kelly: Pitch Usage

Despite a small blip of hope early in the season, Joe Kelly has had a rocky 2015. There have been some calls for him to be sent to the bullpen, but he has shown some improvement in his last few starts. Ian York takes a look at how Boston Red Sox pitcher Joe Kelly has been approaching batters when ahead in the count.

Joe Kelly has started 20 games for the major-league Red Sox this season. For his first 17 games, he pitched 88 ⅓ innings with an ERA of 6.11; in his three most recent starts, he has thrown 17 ⅓ innings with an ERA of 1.56. 

Has Kelly made any changes that would lead to such a big improvement in his outcomes? Probably not; most of the difference is probably luck and chance (his opponents’ OPS over those same periods was .800 vs. .746, and his WHIP was 1.54 vs. 1.34; better, but not nearly to the same extent as his ERA). Still, it would be nice if he has actually done something that would let his tremendous natural stuff lead to better results on the field. What is there to watch for in his start tonight?

He seems to have abandoned the brief experiment of throwing his fastballs a little more slowly, with both his two-seam and four-seam fastballs averaging over 95.5-mph in each of the past three games. It is possible that he is varying the speed of his changeup a little more (following a conversation with Pedro Martinez, in which Pedro recommended that, according to Peter Gammons); in the past three games, there has been 4.6, 3.0, and 4.5-mph difference between the speed of his fastest and slowest changeup, while in most earlier games the difference was more like 2-mph. However, he has had earlier games with similar spreads in his changeup speed, so this is not a completely new thing.

On the suggestion of “joe dokes” on, I looked at Kelly’s pitch usage in different counts. In general, as every fan knows, pitchers tend to throw more fastballs as they fall behind in the count, and more breaking balls as they get ahead of the batter. Kelly does the same:

However, if we look at his last three games, there is an interesting difference; not in all counts, but in the pitchers’ counts, 0-1 and 0-2. In these situations, in the last three games, Kelly has started throwing a much higher proportion of breaking pitches and changeups:

Significant? Probably not. This is probably just chance and variation. But, it also gives the hitter one more thing to think about at the plate. Any time doubt has been created in the hitter’s mind about what pitch might be coming it decreases their chance of getting a hit. Perhaps he has developed a little more confidence in his secondary pitches, letting him set up his fastballs better. In any case, it does give us something to look for in his next starts.

Ian York has written about Koji Uehara, an impressive start by Eduardo Rodriguez, Joe Kelly’s fastballs, the effect of better bullpens on offensive strategy, a look at how Blake Swihart has been doing this season, and Matt Barnes’s first start.

Follow Ian on Twitter @iayork.

Check out part one of Jimmy Wulf’s review of the SaberSeminar.

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.

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