When the Washington Nationals signed Patrick Corbin to six-year, $140 million deal in December, there were questions surrounding whether or not the left-hander could replicate his 2018 campaign that saw him finish fifth in NL Cy Young voting.
Corbin, 29, underwent Tommy John surgery in 2014 and has only eclipsed 200 innings in a season twice. He was an All-Star once prior to his procedure, but it took him five years to earn the honor again due to the long rehab and some inconsistent results.
He finally rose back to prominence just in time for his walk year, finishing the 2018 season with a 3.15 ERA, 1.05 WHIP and 11.1 K/9 — all of which were career bests.
The key to Corbin’s success was the revitalization of his slider. FanGraphs rated it the most valuable slider in baseball last season and he didn’t shy away from using it. Only the Milwaukee Brewers’ Jhoulys Chacin threw more in 2018, making them the only two qualified starters to rely on the pitch at least 40 percent of the time.
Patrick Corbin, Filthy 82mph Slider (slow/release/spin axis). pic.twitter.com/gGgkk6a76k— Rob Friedman (@PitchingNinja) April 13, 2019
Three starts into his Nationals tenure, Corbin’s slider isn’t generating as many swings and misses as it did in 2018 (24.8% vs. 30.2%) and his velocity is slightly down from what it was a year ago. To combat the regression, he’s eased up on his usage of the pitch overall. Instead, Corbin has relied more on his fastball and sinker to complement the wipeout breaking ball.
Last season, Corbin’s sinker was his main secondary pitch. He used it primarily against righties, turning to his four-seamer when facing left-handed hitters. While those splits haven’t changed, they’ve grown more even as Corbin has eased off his slider. He threw sinkers just 10 percent of the time against lefties in 2018 but that number has grown to 15 percent this season. Likewise, righties only saw 15 percent fastballs last year but are now getting them 21 percent of the time.
So far, both of his secondary pitches are generating more swings and misses than they did a year ago. Corbin also has a changeup and curveball that he occasionally mixes into his repertoire against righties, but he’s mostly relied on his top three pitches — especially with two strikes.
That’s not to say all the results have been stellar. While he’s racked up the strikeouts to the tune of an 11.4 K/9, Corbin has also allowed an average exit velocity of 92.6 mph according to Baseball Savant. That mark is the ninth-highest average among pitchers with at least 30 batted ball events so far this season.
Corbin is a below-average pitcher when it comes to inducing ground balls (41.7% rate) and hitters are getting the barrel on the ball in an alarming 10.5 percent of his plate appearances. In fact, the only National League pitchers allowing a higher barrel rate are Jason Vargas, Corbin Burnes and Derek Holland. That trio has combined for a 7.59 ERA with 15 homers allowed in 2019.
Of course, three starts are a small enough sample size to see a wide range of results and Corbin made two of those appearances against the Mets. But between his opponents’ slugging percentage of .444 that ranks among the bottom third of qualified pitchers and FIP of 3.99 that suggests his 2.84 ERA is the result of a little luck, it certainly needs to be a point of emphasis for Corbin and pitching coach Derek Lilliquist moving forward.
Even if Corbin doesn’t have the best slider in the majors anymore, he’s made adjustments that suggest he’s accounted for a step back with the pitch. A prolific strikeout rate is the perfect remedy for shaky power numbers — just ask Max Scherzer — so there’s still reason to believe he can carry over his success from 2018.