The Yankees need help with their starting rotation. At minimum, they need to acquire one starter in the coming offseason. But really, they should get two, especially considering the skepticism around both Justus Sheffield’s and Chance Adams’ ability to start a full season in 2019. CC Sabathia and J.A. Happ, 40% of the team’s starting rotation, are both free agents. Jordan Montgomery will start the season on the disabled list after Tommy John surgery, and it’s unclear when exactly he’ll return. Even if you give the Yankees a fifth starter spot from one of their two rookies or Sabathia returning, there are still holes that need filling.
Patrick Corbin is hitting free agency, and he’s exactly the kind of pitcher the Yankees should pursue. He’s coming off a season as one of the best pitchers in baseball, putting up 6.3 fWAR while making half his starts in one of the most hitter-friendly ballparks in the game. There have been a lot of conversations that Corbin is a one-hit wonder, a pitcher that comes along with an unsustainably good season and never lives up to that again, and is therefore not worth the long term investment. I’m here to tell you that’s false. Everything Corbin has done this season appears to be sustainable, and more importantly, is the culmination of a multi-year process finally bearing fruit.
Since Tommy John surgery in 2014, Corbin’s pitched 85 innings in 2015 and 155.2, 189.2 and 200 innings in each successive season. Obviously 2016 is the real ugly year on his book, with a 5.15 ERA and 4.84 FIP. The remaining three seasons are either excellent – 2015 and this year – and almost exactly league average in 2017. It’s worth looking at his rawest totals, run prevention and the basic process stats, to start:
What this shows is that Corbin’s success isn’t an accident. In his good years, his ERA and FIP are closely related, showing that he’s roughly achieving his talent level. His good and average seasons also boast higher strikeout totals with fewer walks, and critically in such a homer friendly stadium, lower home run rates. His ugly year, unsurprisingly, was disastrous across the board. It was what I call honestly ugly, though, in that there are very clear culprits for the ineffectiveness. That means there are very clear solutions.
Those fixes mostly come down to throwing more strikes. In 2016, Corbin struggled with his walk rate and strikeout rate. And as is often the case, pitchers tend to overcompensate and bring balls closer to the middle of the strike zone, where they get crushed. The 2016 season also has a very interesting tidbit in Corbin’s approach that reveals his bad year is far more of the outlier than his strong campaigns.
In 2016, Corbin threw his four-seam fastball more than any other year of his career, more than 40% of the time. Combine that with his use of the sinker, and almost two thirds of all pitches were the hard stuff. Finally, he tightly worked his changeup into his pitch mix. The problem with this is twofold: first, those two pitches are terrible. Corbin’s fourseamer has registered as positive by run values in just one season since his Tommy John surgery, and that just happens to be 2018, when he threw it only 19.7% of the time. His changeup has never been a plus pitch by run value, and accordingly he’s throwing it less and less as time goes on.
Second, this fastball heavy approach eschewed the use of Corbin’s best pitch: his slider. Now, Corbin’s slider deserves its own article. It’s not just his best pitch; it could arguably be the single best pitch in all of baseball. Over the last two seasons, no starter has a single pitch that’s produced a higher run value than Corbin’s chief breaking ball. Over the last two seasons, no starter has a pitch that’s yielded a greater swing-and-miss rate. Think of Dellin Betances’ breaking ball, but with better command and thrown 40 times a game. It is an unhittable pitch, and Corbin’s growing recognition of that is shown in his gradual increase of the slider in his usage.
This also happens to fit perfectly into the Yankees’ anti-fastball pitching philosophy. The reason why I’m much higher on Corbin having success with the Yankees than most is that he came about the idea on his own. I think one of the reasons Sonny Gray has struggled so mightily in New York is because he was a fastball-heavy pitcher in Oakland, came to the Yankees, and has had trouble changing his usage to better reflect the Yankees’ methods. A pitcher like Corbin already came to that conclusion himself, and should therefore fit easily into what the Yankees are trying to do as an organization without growing pains.
He’s also almost dropped the changeup entirely. At less than 2% usage in 2018, it doesn’t even qualify as a show-me pitch. The role the changeup filled, which was to present a velocity change and keep hitters guessing at the plate, has been taken over by a sneaky good curveball, which at 72 mph is soft enough to present a real change in velocity, playing up the fourseamer and especially the sinker Corbin throws.
Finally, getting into the most granular of process data, Corbin’s positive performance seasons – that is, all of them except for 2016 – also showcase exactly what you want in plate discipline:
There are three components to this chart: O-Swing and Contact rates (pitches out of the strike zone), Z-Swing and Contact rates (pitches in the strike zone) and overall swinging strike rate. What one wants is high swing rates on pitches out of the zone and lower swing rates on pitches in the zone, and obviously lower contact on both.
Since that ugly 2016 season, Corbin’s been extremely good at enticing swings at pitches out of the zone, while more and more of those swings miss every year. This is crucial for a player, and gives credence to just how good Corbin’s breaking pitches are. Professional hitters generally don’t swing unless they think they can hit a pitch, so Corbin’s movement is extreme enough that a whole lot of hitters think his slider and curveball are hittable, only to find they’re not even in the strike zone.
What’s also interesting to me is a gradual decline in Z-Contact rate, or the rate at which players make contact at pitches in the strike zone. If batters continue to miss pitches in the zone, that tells you they’re either guessing wrong on the pitch, or the ball’s movement is so great that even when a pitch is around the plate, it’s difficult to time and connect. Either way, this is good news for Corbin, especially if he plans to change leagues.
Pitching in the American League is much harder than the National, because AL pitchers face Giancarlo Stanton and JD Martinez in the DH slot, while NL pitchers get to face pitchers. Corbin’s ability to miss bats in the strike zone matters a lot here, since the designated hitter is generally much better at laying off pitches than a pitcher batting. As noted earlier, when pitchers struggle to find the zone they often overcompensate and creep back over the plate. Corbin’s performance over the last four seasons shows us that he’s learned to pitch in the strike zone while reducing contact, meaning if he can’t get hitters to chase outside, he’s good enough to come back into the zone without getting crushed.
It’s rare to get a player of Corbin’s caliber available on the open market. In 2018 he was half a win better than Luis Severino and Corey Kluber, a win and a half more valuable than Blake Snell, and virtually identical to Chris Sale. Moreover, his success in 2018 isn’t an aberration, but rather the natural progression of a conscious, deliberate process change.
As he’s worked away from the fastball, and that slider has gotten better and better, Corbin’s gone from a pitcher with very little utility to legitimately one of the best in baseball. Barring injury, which is a caveat we have to apply to all pitchers, there’s nothing that would indicate this kind of success isn’t sustainable, and it’s why the Yankees should make all efforts to land the lefty this winter.