Pebble Hunting: Sean Doolittle and Learning How to Pitch

Back in June, I wrote about Sean Doolittle in a piece for ESPN the Magazine about position players converting to pitching:

Pitching is supposed to be complicated. It's supposed to take years for a pitcher to learn how to pace himself, to stay healthy, to adjust to batters, to get the feel of touchy secondary pitches. But the modern bullpen doesn't reward finesse and strategy as much anymore; it thrives on heat. Pitchers can enter a game for the seventh, eighth or ninth, blaze a dozen fastballs near the strike zone and never worry about developing a changeup or stamina. In an earlier era, someone like (Kenley) Jansen might have spent years learning secondary pitches. In this one, he pumps fastball after fastball. By the time hitters catch up, he's out of the inning.

Even within the cohort of players I was writing about, Doolittle was an extreme case. At the time I wrote that article, he had been pitching for less than a year. He had a total of 26 minor-league innings (50 strikeouts, eight walks, 1.04 ERA) and around seven in the majors (14 strikeouts, two walks, 5.14 ERA). If pitching in relief is simpler than it’s ever been, it couldn’t possibly be so simple that Doolittle had nothing to learn. It would be completely reasonable to think that the Doolittle who finished the season with 73 innings as a pro would pitch a bit differently than the one who began the season with one inning as a pro. So let’s see what he learned in his first full year of pitching.

Hypothesis no. 1: He would throw more breaking pitches.
The simplest stereotype about pitchers-not-throwers is that pitchers-not-throwers are able to make lots of pitches move in lots of different directions; and, furthermore, are able to throw those pitches in a variety of situations and counts, ruining the hitter’s balance and giving the pitcher a bit of sneakability. Doolittle entered the big leagues with a fastball, a hint of a changeup, and a breaking ball that “started as a slider, but (is) starting to look more like a curveball.” In his first appearance, against Texas, Doolittle threw 21 pitches; every single one was a four-seam fastball. He got 14 targets low and away and seven low and in, but he rarely came close to his target anyway.  

He couldn’t possibly throw fewer breaking pitches after that, of course. But, overall, as the season went on, he actually leaned a bit more heavily on his fastball.

• June: 85 percent fastballs
• July: 89 percent
• August: 87 percent
• September: 89 percent
• Postseason: 92 percent

He never attempted to pitch backward in any sort of way. When he was behind in the count in June, he threw a fastball 88 percent of the time. When he was behind in the count after June, he threw a fastball 95 percent of the time. (All on 1-0, in the latter case. On 2-0, 2-1, 3-0, 3-1, and 3-2 counts, he threw 70 fastballs in 70 pitches.)

And he got even less likely to throw an off-speed pitch to steal a strike early in the count. On the first pitch, he threw 77 percent fastballs in June. After June: 92 percent first-pitch fastballs. In one stretch that began in September, he threw threw a first-pitch fastball to 46 consecutive batters. Thirty-eight of those 46 were strikes, which is 82 percent. The league-average on first-pitch strikes is about 60 percent. (Ten were put in play, three for hits.)

Hypothesis no. 2: He would throw more changeups.
Because the changeup is a feel pitch, the sort of pitch that comes with experience and that especially rewards a pitcher who can formulate a plan. Doolittle sprinkled in a few changeups in June, and a few more in July, but never went further with it. Here are his rates against right-handers only, because he throws it against right-handers only—not one against a lefty all year:

• June: 4 percent
• July: 10 percent
• August: 6 percent
• September: 4 percent
• Postseason: no changeups

There’s some value to having the pitch in his pocket and keeping it in batters’ minds, but it wasn’t effective on its own, as around 60 percent of the changeups he threw were balls, and just 3 percent induced a swinging strike.

Doolittle did do some things differently as the year went on. His velocity improved, from a bit below 94 to a bit above, on average. His command seems to be improved; he still misses plenty, and gets swinging strikes even when he misses all the way on the wrong side of his target, but he's not (in the half-dozen games I watched for this) missing as often. His breaking ball also got a bit harder, and the slider that started to look like a curve has gone back to looking like a slider. Here’s his first swinging strike on the pitch this year:

And here’s his last, nearly four mph harder:

And here’s another one in September, nearly nine mph harder than that first one:

And Doolittle has gotten the pumped-up reliever thing going now:

But what made Doolittle so fun at the beginning was how absurdly simple he demonstrated pitching to be. And what makes him so fun now is that, if anything, he has gotten even simpler. There might not be a learning process for him, as long as his fastball is as unhittable as it has been. This might just be how Sean Doolittle is always going to pitch.