Gerrit Cole: Two-pitch pitcher?

Yankees ace Gerrit Cole started the season off on a heater, pitching to a 1.35 ERA through his first seven starts without allowing a single home run, his kryptonite last season. Then, he surrendered eight dingers over his next five starts, covering just 27 innings, and he pitched to a 5.67 ERA overall. In four starts since, Cole has bounced back to allow just one homer in 25.1 innings, warranting a sparkling 1.78 ERA.

That’s the way it goes in a 162-game season; some days you have it, others you don’t, and the reasons why can be internal or external. For example, during that rough five-start stretch in May, Cole faced the Rays — the majors’ best offense by wRC+ and owners of the second-most homers — twice, and they accounted for four of the eight dingers he allowed in that time. Over his past four starts, he’s made good on the opportunity to shut down the Pete Alonso-less Mets and the middling Mariners.

Yet, his opponents notwithstanding, Cole has done something different his last two times out: he’s turned to his four-seamer and slider a whopping 91 percent of the time. That’s the highest rate he’s thrown the pair of offerings across two starts in his entire career. Against the Mets, he turned to the fastball/slider combo 95.8 percent of the time, beating out his previous single-game high by more than two percentage points.

Glancing at the ace’s repertoire, you might wonder why Cole didn’t make this move sooner: on his career, per 100 pitches, his four-seamer and slider have saved him 0.98 and 0.96 runs, respectively. As for the rest of his repertoire, his sinker (which he’s scrapped) has saved him 0.56 runs per 100 and his changeup 0.27, while his knuckle curve and cutter have cost him 0.17 and 0.99 runs, respectively.

One reason Cole has waited until now might be because his slider wasn’t always effective against lefties earlier in his career. In 2015, the pitch saved him 2.09 runs per 100 tosses against opposite-handers, but otherwise, it saved him very little or cost him; overall, his slide-piece cost him 0.23 runs per 100 against lefties from 2013 (his rookie year) to ‘20.

Why did I choose 2020 as a cutoff? Because Cole’s slider’s shape changed in 2021. Specifically, the tall right-hander added three more inches of depth while retaining the same amount of sweep. Here’s a 2020 slider for your viewing pleasure (RIP long-haired Gerrit):

And one from this season (hello short-haired Gerrit):

As more of a two-plane pitch, it stands a better chance at neutralizing lefties (like Daulton Varsho above), and sure enough, since 2021, it’s saved him 1.46 runs per 100 tosses against them, including 2.8 last year and 3.7 this year. This season, he’s sacrificed a little over half an inch of that added drop in favor of an extra half-tick of velocity. That seems to be a winning formula.

Perhaps Cole stayed away from the four-seam/slider combo because, aside from fears of platoon issues, working with a narrower repertoire can stoke worries about stamina. The thinking is that pitchers need to show hitters different looks the second or third time around. But Cole has looked solid through and through in his last two appearances. In fact, the ace struck out his last five Mariners on Tuesday, throwing just two knuckle curves next to six sliders and 17 four-seamers in the process.

Another piece of evidence working in favor of Cole’s new strategy is that there’s one notable starter who’s excelled recently using almost exclusively a four-seam/slider combo: Spencer Strider. The young Braves ace has turned to those two offerings a combined 94.2 percent of the time in his career. He isn’t an exact replica of Cole — his slider is slower and has more drop, while his heater doesn’t have as much run. But he’s about as close a comp as you could get for those two pitches. While Strider hasn’t been as dominant lately, he K’ed nine in his last outing, and I’d bet his poor stretch was more a hiccup than anything else.

Of course, a two-start stretch of four-seamers and sliders galore doesn’t mean that’s the strategy Cole will be sticking with in the long term. But between improved platoon splits for the breaker, a lack of stamina issues so far, a Strider comp, and the potential for the new combo to limit homers — the four-seamer and slider both allow fewer homers per swing than the changeup and cutter, with comparable rates to the knuckle curve — I think that this is a formula worth pursuing going forward.