40 in 40: Justus Sheffield

Justus Sheffield is learning to be himself, and that, to me, is beautiful

One of the most beautiful things about baseball is there are many ways to be a big-leaguer. Mike Trout and his five-tool brethren might gobble up the majority of the highlight reels, but every year during the playoffs there is seemingly a landmark moment from a lesser contributor—Brett “Maverick” Phillips’s clutch single this fall, Howie Kendrick’s go-ahead homer in Game 7 in 2019, Rajai Davis homering off Aroldis Chapman in 2016—that, for a brief and beautiful moment, crystallize and distill the essence of the less-heralded player whose contributions are still key to getting a team towards that playoff Valhalla.

But in the first rounds of the MLB draft, teams are hunting stars. And if a player is selected in those first rounds, that’s the expectation, and the pressure, that will be theirs to bear, coming at them from all directions: team personnel, prospect writers, fans. It’s a pressure that has derailed some promising young careers, and diverted others.

The earliest scouting report on Justus Sheffield from Baseball America describes Sheffield as a “pitchability” lefty who is a “strike-thrower” working in the low 90s. A year later it was noted he’d been up to 95-96. By the time he was traded from Cleveland to the Yankees in the Andrew Miller deal, it was noted he could touch 97. By 2018—when he climbed to #31 on MLB’s Top 100 prospects list, the highest he would ever reach—98 mph.

Jump forward two years, with Sheffield averaging 92-93 mph on his fastball, and it’s pretty clear by now that Justus Sheffield isn’t a power pitcher. Which makes sense; he’s 5’10” and there’s already been a Billy Wagner in this millennium. But even Sheffield says it took him a while to learn to adjust to the idea that he wasn’t going to be “blowing the doors off” in the majors. Throughout the minors, each time Sheffield moved up a level, he’d initially struggle to strike guys out, but then would be given an opportunity to repeat the level and dominate his competition the second time around, posting strikeout percentages in the mid-20s to 30% range. That trend even continued the with Mariners, who yanked Sheff out of Triple-A in 2019 when his walk rate threatened to eclipse his strikeout rate, and sent him back to the safe haven of Double-A, where he mowed down hapless batters in the Texas League before being called up to Seattle at the end of a lost season.

But that’s not to say Seattle wants Sheffield to stretch himself into the power pitcher mold, as ill-fitting as it is. Rather, the Mariners have focused on having Sheffield return to the roots of that earliest scouting report that painted him as a command-and-control, pitchability lefty—an unsexy type in the first round of the MLB draft, maybe, but a valuable contributor to a major-league pitching staff all the same.

The first step in building a pitchability lefty is making sure they don’t walk a godawful amount of people, which Sheffield did in his first 38.2 professional innings between New York and Seattle. The Mariners addressed this by having Sheffield switch to a new two-seam grip that he debuted this year in Spring Training. Changing from a heavy fastball to a true sinker cost Sheffield exactly one (1) tick of velocity, but it also shaved two percentage points off his walk rate, getting him into the single digits. The sinker, it turns out, also performs better than the fastball; it has a Run Value of -2 (remember, negative numbers for RV are good), the same as Kyle Hendricks’, Corbin Burnes’, and Jesús Luzardo’s sinkers in 2020. His four-seamer, by contrast, had a run value of 0 in 2019. Batters slugged .359 against the sinker, which doesn’t feel great, until you compare it to the four-seamer, at .507. (For comparison, the .359 batters slugged against Justus’s sinker is exactly what they slugged against teammate Kendall Graveman’s. Perhaps both of them can take a lesson from the king of sinkers, Marco Gonzales, who sits atop the leaderboard in Run Value on sinkers with -13.)

However, there is something curious that has persisted from 2019 to 2020, regardless of the pitch being thrown. In 2019, the four-seamer, thrown up in the zone, got hit hard almost half—48.4%—of the time. In 2020, despite a pitch that hung out much lower in the zone than its four-seam brother, the sinker got hit hard just as often. However, not every hard hit ball is a barrel, and while Sheffield managed to avoid getting barreled up often on his four-seam in 2019 (4.8%), he did even better with that in 2020 on the sinker (3.9%). There’s a fair amount of ugliness on Sheffield’s Statcast graph, but his Barrel% is not one of them—he ranks in the 89th percentile in the league.

But about that ugliness on the top of his Savant page. The big knock on Sheffield is he doesn’t strike people out. Even that devastating slider only has a Whiff% of 28.5, which puts him squarely in the lower quartile of qualified slider-throwers in 2020, well behind teammate Yusei Kikuchi (38.7%). From a Run Value perspective, however, that slider is worth -5, which puts him alongside Gerrit Cole, Carlos Carrasco, and Max Scherzer, despite all of them having significantly more whiffage on their sliders.

So how does Justus do it? The answer is our old friend, weak contact. Batters hit a pitiful .192 off Sheff’s slider while slugging a truly pathetic .219. For all the devastating, gif-worthy strikeout sliders that get all the attention, this is more often the Justus Sheffield Slider Experience for batters:

Fun fact: this ball came off the bat of Oakland’s Jonah Heim at 103.1 mph. Despite being routinely hit, you can see it had a little extra spice on it by the way Crawford handles the ball, which is then of course reeled in by Ol’ Reliable Evan White at first. Sheffield has been a heavy (50%+) groundball pitcher each of his two seasons with the Mariners, and while there are many things that explain the improvement from his 2019 to 2020 numbers—not least of which is an increased sense of general comfort with both Seattle’s staff and the league as a whole—the fact that he gets to work in front of a trio of present, past (and future?) Gold Glove winners shouldn’t be overlooked.

Those who aren’t Sheffield Believers point to the relative lack of deception in his pitches, as evidenced by his subpar strikeout/whiff metrics. Those who are point to Sheffield’s much-improved performance in the limited sample size of 2020, when he seemingly gained confidence in each subsequent outing, going deeper into games and earning his first MLB win. Indeed, Sheffield has the ideal model for the low strikeout/high WAR pitcher in his own organization in fellow crafty lefty Marco Gonzales, who was the 15th-most valuable pitcher in baseball this year by fWAR (min 50 IP); Sheff ranked 25th, in a year he received 0 Rookie of the Year votes, ahead of Gerrit Cole, Clayton Kershaw, and Tyler Glasnow. After three consecutive years of constant improvement with the Mariners, Marco has finally started to earn some league-wide consideration as a recognized Good Pitcher (or alternatively, Boring-But Good); check Twitter on any given day and you’ll see Yankees fans trying to trade for him, which is always a signifier that one has Made It. It’s uncertain now if Sheff will follow his teammate down the Path of Capability that Marco has forged, but you can’t say he doesn’t have an in-organization blueprint for it.

In 2021, Sheffield will need to stay on the path he’s currently on, continue to improve his command and limiting free passes, and will hopefully refine a little-used changeup that is currently a “meh” pitch but with improvement could be an effective foil for the slider, especially against right-handed batters. It’s always exciting to see someone come into the best and truest version of themselves after trying on the various other identities society has tried to foist upon them. Here’s hoping that Sheffield eventually gets his chance—along with Marco and all the other Mariners who won’t be on MLB’s highlight reel of stars that plays throughout September and October—to be in a big moment on a big stage, and show everyone exactly who he is, now.