Sean Doolittle: Throwing High, Hard and Historic

You know the Sean Doolittle backstory by now, most certainly. The short version for those just joining us is that Doolittle was a first-round pick in the 2007 draft as a first baseman, made it all the way to Triple-A in 2009, then missed more than two years with knee and wrist injuries before converting to the mound full-time in 2012. He made it to the big leagues that year, was a successful setup man in 2013, and now he’s spent the last month as the closer for the best team in baseball.

Oh, and he’s also doing something you’ve never seen before. There’s that, too. Doolittle has struck out 50. He’s walked one. One. Vidal Nuno also has 50 strikeouts; he’s walked 22. We do a lot of complicated math here, but sometimes it’s easy. That’s a 50/1 K/BB. It is, unsurprisingly, the best seasonal K/BB of the more than 27,000 pitcher seasons of at least 30 innings we have in the database. (If you prefer K%-BB%, it’s only the fourth-best ever, but only second-best in 2014 alone. You go, Dellin Betances.) That it’s all but certainly unsustainable over a full season isn’t the point; the point is that this is a real thing that’s happened, and we need to understand why.

Is it velocity? Doolittle throws hard, but not that hard. Averaging 93.9 mph on his fastball doesn’t make him Jamie Moyer or anything, but when you look at the velocity rankings of every pitcher with at least 15 innings in the bigs this year, he’s tied for 43rd. Ernesto Frieri throws harder, and he’s been awful. Veterans barely hanging on like Chris Perez and Kyle Farnsworth throw harder too. Sure, the upper-crust elite closers like Aroldis Chapman, Craig Kimbrel, Greg Holland and Kenley Jansen are also above Doolittle on that list, so outstanding velocity certainly helps, but it alone doesn’t make a pitcher.

Maybe it’s pitch variety. As Jeff recently wrote about Chapman, it’s one thing to have a ridiculous fastball, but it’s entirely another thing to pair it with other offerings that the batter has to worry about, and it’s part of the reason that Chapman has an 18.45 K/9 (!) and a 55.4 K% (!!). Maybe as Doolittle has gained experience on the mound, he’s begun to diversify his… oh.

Highest fastball percentage, minimum 15 innings
Name Team FA%
Sean Doolittle Athletics 85.10%
Kelvin Herrera Royals 78.60%
Trevor Rosenthal Cardinals 78.20%
Addison Reed Diamondbacks 76.70%
Mario Hollands Phillies 76.10%
Tanner Scheppers Rangers 75.20%
Tony Cingrani Reds 74.80%
Michael Kohn Angels 73.00%
Jose Valverde Mets 72.70%
Kevin Quackenbush Padres 71.70%

Nobody throws a fastball as often as Doolittle does, and it’s not even really close. It’s not for lack of trying, of course. In February, Doolittle insisted he was working to add a slider and a change:

“It’s not a secret what I’m trying to do with my fastball,” Doolittle said. “It’s my turn to come up with something else for hitters to think about.”

He had thrown a curveball in the past, and it turned into sort of a slurve last year, with Doolittle using a spike grip. He found he wasn’t getting his hand behind the ball well enough. The pitch wasn’t all that effective and his changeup was only OK.

This spring, however, the slider and changeup look terrific, and one of the best young relievers in the game now might have a choice of pitches.

Doolittle has indeed ditched the curveball entirely, having not thrown it a single time this year, and the change never worked out, having appeared only three times. The slider has become a usable second pitch, especially against lefties; while the fastball/slider split against righties is 90/10, it’s only 77/23 against lefties, and coming very close to a 60/40 split on the first pitch of a plate appearance against lefties. (But only so far as the count is in Doolittle’s favor; approximately 95% of his pitches to all hitters when he’s behind have been fastballs.)

But while the slider is nice to have, and has been effective to the point that he hasn’t actually allowed a base hit off it yet, that’s partially because nearly 50% of them end up as balls; only four times has a slider turned into strike three. Almost all of the strikeouts have come with the fastball. The slider is more of a reminder that it’s there, though worth continued usage in hopes of improvement.

Okay, so he throws a pretty hard fastball, and he throws it nearly all the time. Maybe it’s pitch movement? Relievers like Jansen have had success throwing mainly one pitch, thanks to the ridiculous movement his cutter gets on it.

Well, here’s what a Doolittle fastball looks like:


Here’s another:


And a third, from a few days ago against Brock Holt:


I have to be honest here: those all look pretty straight to me. When it comes to horizontal movement, PITCHf/x doesn’t see anything notable: 48 other pitchers with at least 15 innings this year have better four-seam horizontal movement. Vertical movement, however, is a little different, as Doolittle sneaks into the bottom of the top 10. Expand that to 150 innings since 2012, and he’s in the top 15. I don’t really see it here, but I believe it. Presumably, some about of Doolittle’s success is coming from movement on his fastball.

But no matter how much you believe in the movement on Doolittle’s heater, that doesn’t seem to be enough to explain the 50/1 K/BB. So I figured I’d better go look at the one walk that Doolittle issued this year, which came back in May to Ryan Hanigan.


Now I think we’re getting somewhere. Ignore the hilarious postage-stamp “strike zone” that Gameday overlays and realize that those are A) good pitches, B) only barely not strikes, C) all but identically placed, and D) all high. Doolittle didn’t “miss” when he walked Hanigan. He did exactly what he wanted to do, to an extent that no one else in baseball is willing to try.

No, really. Using the wonderful Baseball Savant, we can isolate only the pitches thrown either in the top third of the PITCHf/x strike zone along with high balls. Guess who’s No. 1?

Highest “high pitch” fastball
percentage, minimum 300 pitches
Name Team %
Sean Doolittle Athletics 46.26%
Michael Kohn Angels 46.01%
J.J. Hoover Reds 42.09%
Trevor Rosenthal Cardinals 41.09%
Chris Young Mariners 40.76%
Jordan Zimmermann Nationals 38.61%
LaTroy Hawkins Rockies 38.60%
Tanner Scheppers Rangers 38.98%
Josh Fields Astros 37.42%
Thomas Kahnle Rockies 37.29%

And now we’ve found the thing, in addition to overwhelming reliance on his fastball, that Doolittle does differently. In a sport where so many pitchers are constantly trying to keep the ball down to induce groundballs and avoid the home run, Doolittle is doing the exact opposite. He’s throwing it hard and high, and he’s doing it a lot:


Nearly 10 percent of those “high fastballs” turn into swinging strikes, easily the highest in baseball. Kimbrel, at just under seven percent, is second. Unsurprisingly, among all pitchers with at least 30 innings, only two have induced higher percentages of hitters swinging outside the zone, but he’s also thrown the third-highest percentage of pitches in the zone. Simply put, Doolittle is throwing strikes, but when he doesn’t, hitters still go after it. It’s hard to think of a better definition for success than that.

Earlier this month, Doolittle indicated that there was a very specific reason he was pitching like that — because he’s a former hitter:

“He throws a hard fastball up in the zone and it’s difficult to get around on it. That’s what makes him tough,” Texas Rangers outfielder Alex Rios said. “If he threw it low, it would get hit, but he throws it at the top of the zone.”

That’s one of the pearls of wisdom Doolittle picked up in his days as a hitter. The third-year reliever was converted to pitcher late in 2011, after an injury to his left knee wrecked his career as a first baseman and outfielder.

“Having been a hitter and realizing how hard hitting is, I’m willing to challenge contact in the zone,” said Doolittle, 27. “A lefty with a little velocity, a little bit of deception, I know how hard it can be to square the ball.”

The deception he refers to matters, too, as Eno Sarris found in early 2013, and it’s important to remember that fantastic 2014 K/BB numbers aside, Doolittle isn’t an out of nowhere story. He was very good in 2013, and he was very good in 2012. Mixing a very good fastball with exceptional control and a willingness to pitch in a way that most hitters don’t see very often is a pretty good way to find success, as is being a flyball pitcher in a power-limiting park with plus outfield defense.

At some point, Doolittle is going to walk another hitter, if only because at some point someone is going to lay off on the high pitch, and then Doolittle’s hilarious K/BB will drop from 50 to some other ridiculous number, then down again when he issues another walk. At that point, it won’t really matter what the exact number is, because it won’t really change what we’ve seen. Barely more than two years since his major league debut, a converted first baseman with essentially one pitch and a nontraditional approach to pitching is having success on a historic level. The A’s believe, clearly, having given Doolittle a 5/$10.5m (plus two team options) extension back in April. Maybe, eventually, Doolittle is going to have to change his strategy to avoid becoming too predictable. For now? He’s doing something we’ve never seen before, ever.

Mike Petriello used to write here, and now he does not. Find him at @mike_petriello or

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8 years ago

Thanks Mike, Good read.
Even more impressive than his K/BB is his 0-1 as a pinch hitter (as a top tier closer).