On Sunday afternoon the Yankees announced Aroldis Chapman would be sent to the disabled list with an inflamed rotator cuff. He’s expected to be out for a month.
It’s a blow to the Yankees, who are hustling in the league’s most competitive division, but the injury helps explain Chapman’s decreased velocity this season, and produces the hope that we’ll see him back up above 100 MPH soon. The flamethrower saw his fastball velocity drop from an average of 100.87 MPH in 2016 to 99.38 MPH this season.
This drop doesn’t take into account the league average one-ish MPH increase in tracked velocity due to MLB’s change from PITCHF/x data to Statcast data. Let’s take a conservative guess at Chapman’s modified velocity being roughly a half MPH off, which would put his fastball down two MPH this season.
Chapman was off to a characteristically imposing start this year, allowing only one run in 11.1 innings pitched over 12 games. But in his two most recent appearances—five days apart—Chapman allowed three runs in two-thirds of an inning against the Cubs (blown save, though the Yankees still won), and one run in two-thirds of an inning against the Astros on Friday (which the Yankees would have lost anyway).
While his average velocity and game performances might be illuminating, the most distinct indicator that something is off with him is found on MLB Statcast’s fastest pitches leaderboard. In 2015 and 2016, Chapman dominated the list so thoroughly they had to create a “Chapman Filter” that would show you everybody but Chapman. In 2017, he’s not even at the top of the list. Call it simplistic or inconclusive, but a guy known for touching 104-105 MPH topping out at 102 MPH is instructive.
Last year batters made contact with 65.5 percent of Chapman’s pitches (honestly, this is higher than I was expecting). League average that year was 78.2 percent. This year Chapman is up to 69.8 percent, but the league average has moved in the opposite direction, at 77.5 percent.
In 2016 Chapman threw pitches that resulted in swinging strikes 18.6 percent of the time—wildly above league average of 10.1 percent. This season his swinging strike rate—still far above the league average, which is roughly what it was last year—has fallen to 14.6 percent. In short: Chapman’s contact rates are up, and his swinging strike rate is down.
Opponents’ batting average against him is way up from .158 last season to .240 this season, but that number is skewed given his .500 BA on his slider, with which he’s allowed one hit in only two at-bats. His fastball is at .192, which isn’t really cause for concern.
To some extent, Chapman’s numbers so far could be considered regression to a realistic velocity. He certainly wasn’t going to throw that hard forever. But the Yankees should hope his stint on the DL brings him back up to the shutdown closer he was for them and the Cubs last season. Opposing batters may be inclined differently.