It started off so well for Corey Kluber. On Monday, he made his first start on a Major League mound since departing the outing after the game of his life with an injury that put him on the shelf for over three months.
At first, it was brilliant — back-to-back Kluber strikeouts of David Fletcher and Shohei Ohtani to announce his return, plus three no-hit innings and a second K of Ohtani to start the fourth. And then, rapidly, it all went downhill. Phil Gosselin, Jared Walsh, and Jo Adell strung together a trio of singles to load the bases; after Brandon Marsh flew out, Max Stassi walked, and Jack Mayfield — he of the career OPS+ of 60 OPS+ — hit a grand slam to give the Angels a 5-2 lead. In just a few minutes, a fantastic start had become a disaster.
So what happened, exactly? Let’s start our inquiry with the Statcast spin rate and movement data on Kluber:
Since Kluber hit the IL back on May 25th, his entire season occurred prior to the “sticky stuff” memo and the Spider Tack controversy that dominated the month of June. As such, it’s not entirely unsurprising that he saw a minor drop in average spin rate; while I cannot confirm that he had been using a banned foreign substance, it’s not out of the question. That said, the decline in spin rate did not necessarily contribute to Kluber’s poor performance — a lower spin rate tends to be better for sinkers, for example, and the spin rate on his curveball is comparable to those of Jack Flaherty and former teammate Shane Bieber.
Something else clearly contributed to Kluber’s fourth-inning meltdown. Fortunately, pitch location can help clarify the picture just a little.
Note: The preceding images are ordered by inning, from first to fourth.
In both the second and third, Kluber was extremely efficient, throwing only eight pitches in each frame, striking out three Angels and inducing a routine flyout and a routine groundout. He was a little wild in the first, walking the third batter of the inning, but he nonetheless was able to work in the shadow zones (the areas near the border of the zone) and generated called strikes on the changeup in the middle of the zone to prevent any damage.
The fourth inning, however, saw two trends. For starters, Kluber began to lose the zone a bit, in large part due to the fact that he could neither generate swinging strikes with the breaking ball below the zone or reliably get the called strike by grazing the bottom of the zone. Additionally, he struggled to locate his pitches up in the zone, often missing high. These factors loaded the bases, which maximized the damage for when he hung a first-pitch curveball to Mayfield up in the heart of the plate:
That’s ... not a good spot for a pitch, and it’s not surprising that Mayfield deposited it over the left-field wall. While you never want to hang a breaking ball, however, they do happen occasionally, and in this case, the real damage came not from this pitch itself, but the pitches over the heart of the plate that resulted in three straight singles to open the inning.
Now, what caused Kluber to lose his command in the fourth inning? One can make the case that it was familiarity, as the damage was done by the middle and bottom of the order seeing him for the second time. It could be operating out of the stretch, as in the only plate appearance from the stretch prior to the fourth inning, Jared Walsh lined out with an exit velocity of 102.8 mph. Perhaps it was fatigue while still finding his rhythm off the IL, as the hanging curveball came on the 30th pitch of the inning; if that ends up as a better pitch and results in a fly out and not a home run, his night looks a whole lot better.
Unfortunately, the truth is that thanks to all of these variables, it’s hard to say for sure what threw a wrench in the Klubot’s works. He did some good things for three innings, and then a whole lot of bad things for one. While that does give some hope that Kluber might be able to be a legitimate rotation option for the postseason, should the Yankees get past the Wild Card round, he will still need to build upon those first three innings in his next few starts in order to turn that hope into legitimate confidence.