Last season, the gap in the Yankees rotation between Gerrit Cole and everyone else made the need for another reliable starting pitcher glaringly obvious. While Jordan Montgomery’s steady development has been a welcome boon to the starting rotation, this offseason’s lottery tickets in Corey Kluber and Jameson Taillon have so far looked more like used up dollar scratchers than Mega Millions winners. Even Domingo German’s return has been somewhat dissatisfactory, as he’s failed to perform up to the level he had in 2019 before serving an 81-game domestic violence suspension. As the club awaits Luis Severino’s eventual return, that unfortunate gulf between Cole and everyone else has remained about as wide as ever.
While some positive regression could be in order for at least the Yankees’ newest duo, it’s unlikely the club has a Cy Young candidate waiting in the wings. Many supporters’ preferred offseason pitching acquisition to that of the Kluber and Taillon signings would have been a trade for the Reds’ Luis Castillo. Through 2019, his age-27 season, Castillo had struck out 578 batters in 519.2 innings with a 3.62 ERA and 1.168 WHIP. Across 2019 and ’20 Castillo recorded more fWAR (6.5) than all but ten pitchers in baseball. Just outside of the game’s upper crest of arms, Castillo appeared poised to continue his steady dominance for at least the next few years with some breathing room away from the wrong side of 30.
As recently as January, the Yankees and Reds discussed a deal for Castillo, but talks between the two clubs stalled when Cincinnati asked for Gleyber Torres, a request the Yankees refused. While Gleyber’s slow start may have some Yankee fans wishing Cashman had pulled the trigger on a swap, Castillo has actually been even worse. Through his first five starts of the 2021 campaign, Castillo has a 6.29 ERA, allowing runs at almost double the rate of his previous season. Worse still, Castillo’s striking out batters at the lowest rate of his career while surrendering hits more often than ever. To date, he’s allowed more hits (32) than any other pitcher in baseball.
Of all the red flags within the statistical profile of Luis Castillo’s 2021 season, the most alarming is that he’s throwing each of his pitches about two miles per hour slower. Over the past couple of seasons, Castillo has been able to keep batters honest with an upper-90s fastball, and put them away with a best-in-the-game changeup, countered by occasional sinkers and sliders.
Luis Castillo, Heart-Stopping 97mph Front Door Two Seamer. pic.twitter.com/NZhboOQF0K— Rob Friedman (@PitchingNinja) August 30, 2020
Establishing this fastball forces batters to expect it, lest they get completely blown away. Then, when he served up a change that falls right off the table at the last possible moment, this happened:
Luis Castillo, Wicked 88mph Changeup...and K Strut. pic.twitter.com/Cy6JPASmhn— Rob Friedman (@PitchingNinja) September 17, 2020
When batters expected a change and got a slider, the contraposed break left them wondering what happened:
Now dealing with a diminished fastball, hitters are having a much easier time spoiling Castillo’s stuff. Since his fastball sits around 95.5 mph instead of 97.5 mph, and still has below average spin, it appears to batters as even more mediocre than the radar gun might now suggest. Without the kind of “rise” or “jump” that makes hurlers like Trevor Bauer and Gerrit Cole’s heaters so effective, batters are teeing off on Castillo’s fastballs. This year, opposing hitters are slugging .500 and .885 against Castillo’s slower four-seam and sinker, respectively. Unfortunately for Castillo, the Statcast data supports the early returns, as hitters have posted an xSLG of .585 against Castillo’s four-seam, and a .762 xSLG against his sinking variant, easily career-worst marks against both pitches.
Considering the waning reliability of his fastball, Castillo has leaned harder than ever on his changeup, throwing it a career-high 39.7 percent of the time. It’s remained extremely effective, maintaining a similar wOBA and xWOBA compared to last year’s version of the pitch. Batters aren’t often able to make solid contact with it due to its solid downward break, but because they’re sitting on it, they’re whiffing and striking out against it about half as often as last season.
The same can be said for Castillo’s slider now, too. Opponents have posted an obscene wOBA of .611 backed by a still terrible xWOBA of .505 against his slider.
Such a rapid decline is unusual for someone still so young and recently dominant, but almost nothing in the numbers suggests he’s due to improve, other than the variance inextricable from a small sample size. He’s given up at least six hits in each of his starts, including four of five turns against below average offenses by team wOBA. Without the power fastball of Luis Castillo’s past, he’s just not the same guy. The dulled weapon degrades the effectiveness of the rest of his arsenal.
While the Yankees would certainly like another ace to complement Gerrit Cole, Castillo has yet to prove that he still is one. If they’re still in need of an arm by the time the deadline comes around, they should take a long, hard look at Castillo before shipping out anything of value for the struggling right-hander. If he can be had for a lesser package than the ones in talks over the winter, and the Yankees feel they can help Castillo regain his edge, he could be worth a shot. If neither of those conditions can be met, they’d be best off steering clear.