Diagnosing Aroldis Chapman’s Wildness

Yesterday, in a game against the Houston Astros, Aroldis Chapman entered the game in the top of the 8th inning and faced four batters; he walked three of them and hit the other. That leaves Chapman with a league-leading 11.37 walks per nine innings, 16 walks and two hit batsmen in 12.2 innings. In his 15 innings last year (including the playoffs) he walked just five batters and hit one.

Obviously these are tiny samples of innings, but going from three walks per nine to over 11 is alarming. His BIS-reported Zone% is down from 43% last year to 38% this year. Here are the locations of his fastballs to right-handed batters in 2010 and 2011 to see where he is missing:

In 2010 the diagonal swath of his fastballs was centered roughly on the strike zone. Since he was throwing in the high-90s and regularly into the triple digits this was fine. He has whiffs on some pitches right in the heart of the zone. But in 2011 that swath of fastballs is centered higher and further inside. He get some swings on his out-of-zone pitches — particularly those inside — but for the most part they end up as balls.

There is also a conspicuous difference in Chapman’s “release point.” The Pitch F/x system estimates the trajectory of each pitch and then reports where it was 50 feet from the plate. This is too close to be the real release point. We don’t know exactly where the pitch was released, but it is best to pull the pitch back some. For tall pitchers with a long stride, like Chapman, 53 feet is a good estimate. See Mike Fast’s great article on release points for a detailed discussion. Here are the locations of Chapman’s fastballs when they were 53 feet from the plate, an estimate of release point.

It looks like he is releasing his fastballs about six inches higher and closer to the center of the mound: so more over-the-top and less 3/4 delivery. Again this conclusion is hard to make without the actual release point, and because the Pitch F/x system is more noisy at the release-point end of the trajectory than the plate-location end. So I wanted to see if I could back it up with photographic support. It was hard to find pictures from the head-on angle, but it does look like he has a slightly more over-the-top delivery in 2011 than in 2010 and definitely more than in 2009 during the World Baseball Classic.

This suggests, though definitely not conclusively, that Chapman may have “lost” his release point. And it is possible that this “lost” release point plays a role in his huge walk rate.

Dave Allen's other baseball work can be found at Baseball Analysts.

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12 years ago

Pitching coach Price has said it’s release point, that he’s actually coming too far around the ball. See John Fay’s blog

12 years ago
Reply to  Dave Allen

Diagnosing pitching problems as a drop in arm slot is kind of a pat response for pitching coaches, from what I’ve seen. Never heard someone coached to drop down (except when going full side arm or something, obviously).

12 years ago
Reply to  Dave Allen

TCQ: If I recall, one of the first things Bruce Walton did with Morrow is suggest that he move to a 3/4 slot instead of an over-the-top delivery (though I could be wrong). Though I agree that it often seems used as the default problem.

12 years ago
Reply to  Dave Allen

I haven’t noticed the arm slot when watching him, just reporting the source. Anecdotally he seems to struggle when entering the game with runners on base (though that wasn’t the case last time out) and when he pitches more than back-to-back days. Seems like a guy who’s destined to start because of the repeat days problems and the fact that when he’s on he wipes out every hitter who steps to the plate. Rarely has problems with one batter and adjusts to the rest of them. Either he’s on or he’s not, but when he has it down that day-look out.