Despite his age, Aroldis Chapman has a chance to get even better

As Aroldis Chapman’s average fastball velocity has steadily fallen from 101 mph in 2016 down to a (comparatively) measly 98 mph this past season, so too has his effectiveness. While he’s only regressed from the best reliever in the league to one of the best, he will continue becoming easier to hit as the pitch he throws almost three-quarters of the time slows down.

Still throwing cheddar at 32 years old, he likely (and correctly) considers himself among the game’s most dominant arms. However, as he nears his mid-thirties, the day when Chapman’s unable to overpower batters with the same regularity is probably closer than he, or Yankee fans, would like to imagine.

Yet Chapman has a clear path to maintain his edge, and perhaps even regain his status as the best closer of his generation by fully incorporating a pitch he’s experimented with over the years: his splitter.

In September, Chapman threw all four of his 2020 splitters in two back-to-back outings against the Blue Jays. Back then, Peter Brody wrote an excellent piece outlining the history and efficacy of Chapman’s experimental splitter usage. Crucially, Peter noted that Chapman was no stranger to the splitter, as Aroldis had thrown the pitch in spring training as early as 2013. That was the last time Chapman threw the pitch in a game until the outings against the Jays.

From those four split-finger fastballs, Chapman generated four swings and misses, three of which ended at-bats in a strikeout.

Some of the pitch’s success here is no doubt due to the fact that the batters facing Chapman were expecting nothing of the sort. When he unexpectedly employed a secondary pitch other than his slider, hitters stood little chance of surviving. Since no pitch in the history of baseball has guaranteed a swing-and-miss on every toss, it’s an obviously unsustainable rate of production. But Chapman’s preexisting repertoire would only be enhanced by adding in a regular splitter.

It’s a particularly difficult pitch to throw consistently, but unusually large hands make it easier to bury a baseball between the middle and forefinger. At a long limbed 6-foot-4, Chapman has the ideal physical equipment to execute the pitch consistently. Unlike a fastball, with which greater backspin produces the perception of a rising effect that makes the game’s best (like Gerrit Cole and Trevor Bauer) so unhittable, a great splitter, like a knuckleball, is most deceptive with the least spin. When a splitter is thrown with the ideal location and spin, it has a sudden vertical break just as it’s about to enter the zone. Chapman’s was so devastating that of the three splitters that Statcast correctly identified, Chapman’s average spin was lower than that of Steven Wright’s knuckleball.

The one risk with Chapman’s splitter stems from its variant break. Of the four Chapman threw, one was read by Statcast as a slider.

By supinating his wrist slightly, Chapman cuts his splitter like a slider, causing it to break glove-side and opening an opportunity to cross up a catcher expecting the pitch to break in the opposite direction—something particularly harmful in high-leverage, late-game scenarios, even if Chapman were to earn the swing-and-miss. Therefore, if Chapman is to move forwards with the pitch, he’ll need to iron-out his wrist positioning on release for a more consistent break.

The Yankees’ present-day split-finger wielder, Masahiro Tanaka, relies on the pitch in all counts, throwing it almost as often as he does any other pitch. However, he throws it just 87 mph, and only five mph slower than his average fastball, getting hitters off-balance to induce weak contact more often than completely fooling them into swings and misses. Chapman, if he were to incorporate the pitch on a full-time basis, would more than likely still rely on his all-time fastball, using the splitter as a secondary out-pitch, after the slider.

Unlike Tanaka, Chapman’s power pitching would interact symbiotically with a splitter, as his 91-mph version of the pitch has a greater differential between his fastball than Tanaka’s. Further, with a “rising” heater and a tight left-to-right breaking slider, his splitter would offset each pitch’s movement with a sharp “falling off the table” action and a slight arm-side, changeup-like fade. As Peter noted in his aforementioned article, Chapman could pitch to lefties and righties with equal effectiveness by adding in a splitter that breaks away from righties as the slider already does to lefties. Adding this kind of power-splitter into his pitch-mix would make Chapman a more complete pitcher, a rare feat for a reliever already possessing two supremely dominant weapons.

In fact, were Chapman to regularly incorporate a splitter, his closest historical point of comparison might be the seven-time Cy Young winner, Roger Clemens. Clemens is undoubtedly one of the greatest starting pitchers of all time, and deployed “Mr. Splitty” with greater regularity than either his slider or curveball.

Without pitch frequency data before 2002, or any tracking data on Clemens whatsoever, it’s impossible to say exactly how Chapman’s splitter compares to Clemens’ in terms of velocity or spin. Chapman’s velocity and strikeout rates do compare favorably to Clemens’, even when he was throwing gas in his early days on the Red Sox.

An awesome splitter is one of the game’s hardest pitches to hit, but also one of the hardest to throw. Against all pitches, since 2008, major league hitters have recorded a .318 wOBA. When isolating splitters, which make up just 1.5% of all pitches thrown, batters did far worse, posting a combined .262 wOBA. The splitter’s unique movement and scarcity make it a better than average offering for any pitcher that can handle it. If Chapman’s capable of replicating the few, but elite, splitters he threw in 2020, there’s no reason for him not to do so with greater regularity moving forwards.

As his velocity continues to ebb with age, a splitter could be just the weapon that could delay his decline in the long-term, or even improve his performance the short-term. Aroldis Chapman will be an elite reliever in the major leagues even if he throws his fastball in the mid-90s (a drop that seems impossibly distant for one of the game’s all-time flamethrowers), so long as he adds a second breaker to compliment his slider.