In the case of Gerrit Cole’s disappointing 2016, we should first say that we’re not entirely sure how wrong things went.
FIP — the well-known measure that strips away things a pitcher “doesn’t control” and judges performance based on strikeouts, walks and homers — produced a 3.33 for Cole’s season, merely a small step back to 2014. xFIP, which further assumes that pitchers are likely to regress toward the average HR/FB%, was less rosy and saw a 4.02, the first ERA, FIP or xFIP on Cole’s major league page that crossed the 4.00 threshold. Most alarming was DRA, the comprehensive Baseball Prospectus model that assigns credit/responsibility for a wide variety of things, including batted balls and framing. It levied a 4.97 — 114th out of the 144 major leaguers with 100 IP.
Which of those alarms you choose to sound is a question of both philosophy and constitution that I don’t have time to grapple with at the moment. Cole was a burgeoning ace in 2015 — with a 2.60 ERA in 200+ innings and the peripherals to back it up. In 2016, he was very much not that, and if not for the big velocity, you may have had trouble convincing someone that he inspired this 2016 Baseball Prospectus annual comment.
Cole put together the finest season of his still-young career, topping 200 innings for the first time and producing new career-best marks in every one-stop pitching metric known to man (and presumably some known only to apes). How did he make the leap? According to Travis Sawchik of the Pittsburgh Tribune-Review, Cole placed greater emphasis on taking care of his body. That meant embracing the ancient technique of "cupping," as well as using data collected by a BioHarness—a strap that tracks heart rate and other physiological metrics. Cole has always had the power stuff to be a front-of-the-rotation pitcher, and if his new-found attention to detail proves legitimate, this is the beginning of an era of dominance.
So who or what robbed Cole of that dominance? That’s our mystery. The sense of urgency is entirely up to you.
Two suspects immediately crowd our field of vision: injury and a very high BABIP. In a bizarre way, this is encouraging — like finding that the missing child was probably taken by the estranged parent. It is not good, but you know what you’re dealing with.
The injury was originally a triceps problem that sliced his season into two pieces, and then an elbow problem that seemed to stem from the triceps upon his return. The BABIP is trickier, especially considering our expanding knowledge of how pitchers might control or influence batted balls, but anyone who has dipped a toe into the saber-pool knows to expect regression from extreme BABIPs like Cole’s .345 (fourth-highest in the majors among pitchers who threw 100 innings).
We cannot simply be satisfied with pointing at the BABIP as the lone conspirator against Cole, though.
Being the week that it has been, an investigation is necessary to determine whether there were an inordinate number of balls misplayed by the center fielder (the now-displaced Andrew McCutchen). And while Cole allowed more hits per batted ball to center than usual, it wasn’t anything I’d be willing to call an effect, and it barely accounted for any extra-base hits. We can almost certainly discard that theory.
As the unconventional hypotheses dwindle, trying to snatch the interesting from the jaws of the mundane becomes difficult. How many line drives did he allow? Sure enough, he gave up a lot of them — sixth-highest rate among that same group of pitchers who threw 100 innings. Not great. He checked out well, however, at limiting exit velocity and hard contact. And in the midst of the unexplained home-run boom, Cole surrendered fewer home runs per fly ball than any starter not named Rich Hill. OK, so he tied with Miguel Gonzalez.
Still. How do you stay good at so many things and turn in worse results? As usual, pitching has hidden its complex nature in a guise of simplicity. Gerrit Cole, top draft pick, power pitcher, should not be complicated. He throws a fastball that averages 95 mph, and a slider than can clock in anywhere between 85 and 89 mph. That should be hard to hit.
And yet he has never really missed bats in the way those pitches would suggest he could. His apparent 2015 breakout owed more to minuscule walk and home-run rates. Nonetheless, his bat-missing abilities progressed, as he eclipsed the 10 percent mark in swinging-strike rate for the first time, largely on the back of that heralded slider.
Then those whiffs slipped away, and maybe that’s exactly what happened. It doesn’t take a seasoned investigator to follow the thread of the slider-heavy breakout stars grouped in with Cole. Chris Archer struggled mightily with the long ball, in addition to his constant battle with the strike zone, and Sonny Gray found himself trapped in a much darker version of Cole’s twisting timeline.
Here we come to the usual suspects.
In our pursuit of cold, hard evidence, we must sometimes accept faint tracks as our best way forward. This, an instance where a “feel pitch” looks to have gone awry, may be one of those times. These tracks are not terribly hard to see: His slider didn’t break as much. In particular, it didn’t pack as much downward motion in 2016, or even at the end of 2015.
Horizontal movement? Also down.
Following the tracks is a bit more difficult, as hitters come into play. It may be that Cole was walking into a trap in 2016 no matter how much depth his slider retained. Batters began to withhold their swings on the screaming sliders outside the zone that overwhelmingly favored Cole — the ones that turned into dribblers or foul tips into the mitt.
Instead, they waited for the ones that sat up above the knees, and then they roped them into space between the infielders and the outfielders and took a base or two.
Ending a plate appearances on Cole’s slider made you a league-average hitter in 2016, whereas in previous seasons it made you a defense-first middle infielder trying to avoid the Mendoza Line.
Is it possible Cole simply lost some feel for the slider? PITCHf/x data shows a bit of a release point change to go with the decrease in depth on the pitch, and we also know he added a knuckle-curve upon his return from the DL. Is it possible all of those crumbs lead us back to his triceps issue, or whatever underlying injury he was nursing? Or did he just lose confidence in what had been his primary swing-and-miss pitch?
Maybe you trust Cole’s dominance to find its way back. Aces have undoubtedly been formed from less than Cole’s raw materials.
But I don’t think we can consider this case closed when his career thus far has presented the above-average profile of a contact-oriented flamethrower more often than the elite profile of a power ace. It remains possible that we’ve looked at this wrong the whole time — that 2015 is simply the mystery of an impostor (figuratively), not the last known sighting of a monster on the mound.
. . .
Zach Crizer is a featured writer at Beyond the Box Score. You can follow him on Twitter at @zcrizer.