The Yankees need Aroldis Chapman’s velocity to return eventually

We’re only one game into the season, but there’s already a red flag going up in the Yankees’ bullpen. Aroldis Chapman doesn’t have much life on his fastball right now. On the one hand, it’s still March. It might be a bit early in the year to truly start worrying. On the other hand, his velocity sits so much lower than what might be considered normal for this time of year that it very well could be an ill omen. Regardless, the Yankees ought to monitor Chapman’s velocity closely because if it doesn’t pick up, it could have significant effect on the team’s bullpen plans this season.

Chapman’s diminished velocity was on display throughout spring training and continued yesterday. In the ninth inning, the left-hander threw 18 pitches, 12 of which were fastballs. The average velocity on those pitches was 95.1 mph. Two fastballs did touch 97 mph, but neither went for strikes.

Even for just one outing, Chapman’s velocity looked severely diminished from what it averaged just a year ago. In March 2018, Chapman threw 122 fastballs with an average velocity of 98.1 mph. However, that number might prove misleading. Baseball Savant also registered 25 pitches as sinkers during that month. The average velocity of those pitches was 100.1 mph, making Thursday’s average velocity a bit more eyebrow-raising.

Pinpointing the reason for diminished velocity is certainly difficult. For all we know, Chapman isn’t dealing with any injuries. By all accounts, 2018’s knee injury completely healed. We also haven’t heard anything about his shoulder injury from 2017 in ages. Unless he’s hiding something, we can rule out injury.

There always exists the possibility some age-related decline has set in on the 31-year-old’s left arm. Maybe it will just take some time for the fastball velocity to come back. He does have a history of peaking sometime near midseason. Consider this visual:

BrooksBaseball.net

Chapman did experience a little bit of decline last year. In addition to his overall fastball velocity going down, his Hard Hit Percentage checked in at a career-high 34.5%. His walk rate stood at 14.2%, the highest mark since 2011. If his numbers in these categories slip a little more this season, and his fastball velocity stay down, it could spell a significant difference in performance. Look no further than Tommy Kahnle’s 2018 season to see what could happen to a pitcher without quality velocity or decent fastball command.

Of course, saying it “could happen” doesn’t indicate any level of certainty. Fortunately for Chapman, he does have a quality slider that he’s used more in recent seasons, and he could lean into it even more if the fastball doesn’t completely bounce back. Ben Clemens of FanGraphs did a close look at Chapman’s slider, and he found hitters whiff at Chapman’s slider at a ridiculous 47.9% rate when the pitch is in the strike zone, a percentage that puts him comfortably in first place around the league.

Still, pinpointing why so many hitters whiff on Chapman’s slider even when it’s in the zone is a bit of a mystery. As Clemens speculated, “Maybe it’s a function of hitters gearing up to hit the fastball. Maybe it’s a function of the 14.5-mph difference between his fastball and his slider. Maybe his delivery is just deceptive.” But if hitters don’t have to gear up for a wicked fastball, or if there’s no longer a such a velocity disparity between the two pitches, one could argue Chapman shouldn’t be the ninth inning option.

We’re still a long way from really worrying about Chapman’s velocity, but he is certainly a pitcher to keep an eye on early this Spring. If stronger showings on the radar gun don’t come soon, better teams than the Orioles will get to him. If he doesn’t pick it up, the Yankees might be better off by giving the ninth to someone else.