Which Yankees pitcher had the best fastball in 2020?

Despite losing several projected contributors to injuries, the Yankees still employed a few standout arms throughout the 2020 season. Though they couldn’t eventually match the depth of Kevin Cash’s infamous “stable,” the upper-echelon of Yankee pitching was at least as capable of bringing the heat. With all due respect to Tommy Kahnle and Luis Severino, each having proved capable of approaching the century-mark in 2019, their presence on the Injured List for the entire 2020 season rendered them ineligible for this year’s honor. Of the Yankees’ finest fastballs, the three pitchers atop the totem Gerrit Cole, Aroldis Chapman, and Chad Green.

A hypercar needs more than a turbocharged engine to win a race. Just as important are its smooth transmission to use power efficiently, and a steady hand to guide the wheel. While Cole, Chapman, and Green each proved capable of reaching elite top-speeds near triple-digits, they also extracted value from their varying abilities to create perceived rise and control the pitch.

Of the three, Aroldis Chapman is clearly the hardest thrower, even as his velocity has regressed in recent years. His average fastball velocity of 97.8 mph easily tops Cole’s 96.7, as well as Green’s 95.5. Even when you factor in the fact that the starter of this group, Cole, might refrain from firing away on every pitch as Chapman might to close out a game, his top end was considerably lower than Chapman’s. Chapman’s fastest pitch of 2020 was clocked at 101.5 mph, and cracked 100 in 15 of his 144 fastballs. Cole, alternatively, only did it once, despite throwing more than four times as many fastballs. Green, in this category, simply lacks the juice to compete with the other two, as his fastest pitch of 2020 sat at 98.1 mph.

Though Chapman has the best engine on the Yankees, it was Cole who had the team’s most efficient transmission. His fastball’s average spin rate was the 25th-best in MLB, a good bit better than both Green and Chapman. Chapman and Green each threw a ball with as much or more “rise” (less vertical drop) than Cole, but Cole’s ball had the fourth-best spin efficiency in the majors (99%). Cole’s fastball gets excellent rise like Green and Chapman’s, but also runs to his arm-side a ton, 50% more than fastballs with a similar velocity and release point to Cole’s, and more than the other top-97 fastballs ranked by rise. Chapman and Green essentially match Cole’s rise on the vertical plane, but get doubled up by Cole’s horizontal movement. Cole’s fastball gives batters a more complicated pitch to deal with, as each offering moves significantly on both the X and Y axes.

In terms of value, the race between the three gets much closer. Despite his aesthetic deficits in velocity and movement, Green’s fastball actually fared the best of the three against real live major league hitters in 2020. Per 100 fastballs, Green’s fastball rated as the ninth best among all pitchers who faced at least 50 batters according to Baseball Savant’s run value. According to xwOBA, Green wasn’t much worse, as he finished 14th with a .237. While he only finished 25 plate appearances with fastballs, Chapman’s heater was almost as effective as Green’s in terms of run value per 100 pitches, and even better in terms of xwOBA, as batters hit just .095 against the pitch.

After creating a greater run value from his fastball than any pitcher over the entire 2019 season, Cole saw considerable regression in 2020. His well-documented struggles to keep the ball in the park were borne out in the data. Batters’ numbers across the board climbed significantly, but no data-point was more eye-opening than Cole’s jump from a .321 xSLG in 2019 to a .478 xSLG in 2020.

Since Cole improved as the season wore on, it’s hard to imagine that the latter figure is the Cole we’ll see for the rest of his career. In all likelihood, at least as long as he stays healthy, the real Gerrit Cole is somewhere in between the two numbers, and if anything, closer to 2019’s four-times greater sample size. Moving forward, Gerrit Cole is a safe bet as the owner of the Yankees’ best fastball in terms of bulk, as he’s got the longest track record, largest work load and the filthiest moving pitch of the three.

(Also, Cole does a better job of locating his fastball than the other two, as he allows his natural run to dominate the top, inside part of the zone—to a right-handed batter—something that should help him dominate again in the future.)

In terms of the best fastball between the lines in 2020, Cole’s home run-stricken reality precludes him from winning this race. Chapman and Green each threw their fastball upwards of 70% of the time, therefore generating the bulk of their production off of the single pitch. Green recorded slightly better hit, homer, and walk rate stats than Chapman, while Chapman won the strikeout battle. Despite Green’s somewhat disappointing 3.51 ERA, especially compared to Chapman’s mark of 3.09, he bested Chapman’s 2.70 xERA with his own 2.20 xERA.

2020’s mini-march to October created weird disparities between expected and actual stats, but when eliminating factors outside of his control, like hit distribution, park factors, and defense, Green was much more effective than the sticker shock that his ERA might induce. Even with a slight lead as per the sabermetrics, the biggest differentiator between Green and Chapman was Green’s workload. While Chapman threw just 11.2 innings after recovering from COVID, Green threw more innings than any other Yankee reliever (25.2).

Cole is certainly the most valuable pitcher of the trio, with the ability to throw many more innings and the likelihood of positive regression over a full season. Chapman is the most dominant of the three, a perennial candidate to pace the league in strikeout rate with his unparalleled velocity, superior slider, and—fingers crossed—splitter. Among the 2020 Yankees’ fastballs, however, Chad Green’s mid-90s rising variation proved to be the most valuable.