Gerrit Cole and the Disappearing Curveball

Gerrit Cole’s command of his pitches and deception in using them has vaulted the 24-year-old from “pretty good starter” to one of the league’s best. We take a closer look at exactly how he’s done it. 

Gerrit Cole took home the honor of NL Pitcher of the Month for April after winning four of his five starts and striking out 35 (to just eight walks) in 30.2 innings. Pirates fans have to be tickled with his development, as Cole has put up solid campaigns in his first two seasons with Pittsburgh and now posted career-bests in WHIP, FIP, K/9, K/BB, and opponents’ batting average through the first month of 2015. It’s enough to start thinking about where Cole ranks among the NL’s best starters and whether his performance thus far is sustainable enough to put him in the Cy Young conversation.

April 13 2015: Pittsburgh Pirates starting pitcher Gerrit Cole (45) delivers a pitch during the game between the Detroit Tigers and Pittsburgh Pirates at PNC Park in Pittsburgh, Pennsylvania

A funny thing happens when you start looking at the details behind Cole’s numbers—no one seems to agree on what his breaking ball is. He actually has two—a curve and a slider, the latter being the better and more-utilized of the pair—but they’re so similar in velocity, break, and spin that classification confusion abounds across the various platforms that gather pitch data. For example, so far this season there have been six pitches which were labelled curveballs by Fangraphs but called sliders by Brooks.

What’s certain is that 2014 was the year Cole started to really implement the curveball in his repertoire, taking a few notes from A.J. Burnett and using it more effectively late in the season. In fact, the home stretch of 2014 was Cole pitching at his very best, finishing with a stretch of three straight dominant starts and six of nine in which he managed a WHIP of 1.00 or less. That run of success coincided with Cole throwing a lot less of his four-seamer and an increased dosage of his breaking pitches:

Cole Chart 1

With the rave reviews and results of his pitching, it stands to reason to think Cole’s hot start to 2015 is largely due to a continued commitment to the breaking ball. Well, not exactly:

Cole Chart 2

Even with that six pitch disagreement mentioned above, Cole’s gone to his curveball only a handful of times. For the most part he’s using it as a backdoor breaking pitch to lefties. Cole’s fastball-slider combination is usually enough to retire righties and, throwing in his changeup in the mix, it makes sense that he barely throws the curveball to same-handed hitters.

MLB: MAR 09 Spring Training - Twins at Pirates

If he has his way, Cole hammers the lower-outside edge of the strike zone against righties—in 2013, he threw 34.57 percent of his pitches to right-handed hitters in that quadrant and in 2014 it ticked down slightly to 29.62 percent. This season, he’s continuing to pepper the zone low-and-outside against righties to the tune of 31.3 percent of his pitches, but now mixing in a good dose of heaters in on the hands of righties with the occasional slider. This may diminish if hitters become more selective against Cole, but for the time being, he’s living on the edges of the zone and loving it.


Cole Chart 3

Against lefties, he’s tinkered with all four of his secondary pitches as the primary complement to his fastball. It seems this season, Cole’s slider is the answer. In his three starts against lineups featuring three or more lefty hitters, Cole’s thrown his slider 17 percent of the time, but it’s been very effective against them. Overall, opposite-handed hitters are hitting .125 against his slider and have only put eight of the 34 sliders they’ve seen in play.

His biggest test against lefty hitters came against Chicago on April 29, facing a lineup featuring Dexter Fowler, Anthony Rizzo, and Miguel Montero. Cole scuffled a bit early, allowing singles to all three of the aforementioned lefties in their respective first at-bats. Not coincidentally, Cole only threw fastballs and sinkers to them. After those first three at-bats, the lefties in the Cubs lineup went 0-for-7 with four strikeouts in eight plate appearances, and they saw nearly as many sliders (9) as sinkers (14).

Cole has a devastating arsenal of pitches with or without his curveball. With the quality of his fastball, slider, and sinker, Cole shouldn’t feel pressure to overuse his curve—keeping it to favorable counts against lefties is likely his and the Pirates coaching staff’s plan, though if hitters adjust to Cole’s slider we may begin to see more of it. It never hurts to have another option in the bag of tricks when you need it. With Cole’s ability and improving command of his pitches, this could be a very special year for the 24-year-old hurler and one in which he ascends to the role of Pittsburgh’s undisputed ace.

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