The lasting image of Aroldis Chapman’s 2019 season is a painful one: stunned, standing at the foot of the mound in Houston, wearing a shocked smile as Jose Altuve rounded the bases after unloading on a hanging slider for a walk-off home run that eliminated the Yankees in Game Six of the ALCS.
It was just the second hit Chapman allowed in 5.1 innings of work during the 2019 postseason, but one that was likely difficult to forget during the offseason. Now, as Chapman enters his age-32 season, the question will be whether the southpaw flame-thrower can continue to produce at his usual level, even if he loses a notch or two on his trademark, high-octane stuff.
2019 Stats: 57 IP, 38 H, 2.21 ERA, 2.28 FIP. 37 SV, 13.4 K/9, 3.9 BB/9, 6.0 H/9, 0.5 HR/9, 1.5 WAR
2020 FanGraphs Depth Chart Projections: 65 IP, 2.81 ERA, 3.00 FIP, 34 SV, 13.76 K/9, 4.09 BB/9, 0.94 HR/9, 2.1 fWAR
Chapman is known for his electric fastball, and while that heater still packs plenty of punch, it has continued to lose juice as time passes. The 2019 season was no different, as his average fastball velocity dipped to “only” 98 mph.
Of course, Chapman can still find plenty of success with that velocity:
The potential issue is that Chapman’s fastball has dropped roughly a full mph each year since 2016, when it averaged 101.1 mph. If that trend continues, and Chapman is closer to the 97 mph mark in 2020, his overall numbers could start to decline. More pitchers than ever are throwing above 95 mph, and Chapman will only become more ordinary as his fastball loses life. At the start of the 2018 season, FiveThirtyEight published a piece on hitters posting a higher OPS against fastballs 95 mph and above than ever before, and Chapman is drawing closer to that average velocity mark.
Of course, a fastball that is no longer tops in the league, but still awfully good, can be perceived as the best of the best when paired with a strong secondary pitch. Chapman’s slider reached its highest value of his career, per FanGraphs, as he continues to use that pitch more to counter his decreasing velocity.
The issue with Chapman’s slider was the rise of more than 100 points in opponents’ xSLG against the pitch last season. Will he be able to miss bats with his slider while continuing to rely on it more, or will hitters become even more familiar with it?
Chapman’s strikeout percentage dropped more than seven percent from 2018 to 2019, but on the positive side, his walk rate dropped four percent. If Chapman can alleviate traffic on the bases, his declining strikeout rate would be much less of an issue. He still has a great fastball and his slider is efficient enough to pair with that heater, so as along as he doesn’t experience too much of a drop in fastball velocity, he should be in for another productive season. With other quality arms in the bullpen like Zack Britton, Chad Green, Tommy Kahnle and Adam Ottavino, Aaron Boone should have little problem keeping Chapman fresh and maximizing the value on that fastball as the season moves along.