Corey Kluber Might Have the Best Pitch in Baseball

I don’t know what brings you joy. Baseball, probably, or else you’re hopelessly lost on the internet. Chances are, you’re a fan of a team, so you root every day for that team’s success. Me, I’m less a fan of a team, and more a fan of players and subjects. One of the things that’s been bringing me joy is observing Mike Trout climb up the WAR leaderboard. It’s amusing because, obviously, Trout missed about six weeks due to injury, and it’s hard, obviously, to accumulate WAR when you miss a quarter of a season. Trout is amazing.

There’s a slightly lesser version of that same exact story. The best pitcher in baseball, by WAR, is Chris Sale. That’s not very surprising, recent stumbles aside. Yet, the second-best pitcher in baseball, by WAR? That would be Corey Kluber, who missed a whole month due to a back problem. Even though a month is a long time, in baseball terms, Kluber has put that unfortunate episode behind him, even threatening to create something of a Cy Young race. Kluber, generally, has been pitching like Corey Kluber. Just, an even better version. The Kluber of today might have baseball’s best pitch.

You know the pitch I’m talking about. It’s not like it’s something he just created out of thin air. If you’re familiar with Corey Kluber’s body of work, you know he’s long had an insane-looking breaking ball. You might be tempted to call it a slider. Or, you might be tempted to call it a curveball. According to Kluber, it’s neither. It’s just a breaking ball, a spinny thing, and here are a couple of visuals, from a center-field camera angle.


It’s not a pitch with a whole lot of drop. Never has been. The success is more about the blend of velocity and lateral, sweeping movement. And, as you’d figure, it’s also a function of Kluber’s command. A good pitch is only a good pitch if it goes around where the pitcher would like. Kluber has mastered this weapon, even more than he already had, and as evidence, consider first that Kluber is throwing this pitch more now than ever.

The frequency is right around one out of four. The previous high was around one out of five. That’s hardly earth-shattering, but it’s movement nonetheless, the kind of shift that doesn’t happen by accident. Now, what’s something you might expect when a pitch is thrown more often? Opponents, in theory, will look for that pitch more often, and you could see the pitch generate slightly worse results. Not so. Check out Kluber’s breaking-ball whiff rates.

To really focus on the point: Kluber is throwing the breaking ball more than ever, and it’s missing bats more than ever. The pitch is finding more success, even after having become more exposed. As another proxy indicator, we can look at the counts in which Kluber has gone to this weapon.

What we’re dealing with, for the most part, is a putaway pitch. It has all the characteristics of a putaway pitch, and Kluber most likes to use it when he’s already got two strikes. But then look at the other line. Kluber is also at a career-high in breaking-ball usage in non-two-strike counts. Pick a measure. Any measure. It’s likely to tell you that Kluber really, really loves this thing.

Let’s get back to the earlier claim. Is this the best pitch in baseball? At the very least, there’s an argument. Firstly, I’d like to eliminate relievers from consideration. There are relievers who throw truly outstanding pitches, but relievers and starters are effectively playing different games. The best pitch out of the bullpen would be worse if it had to work for five or six innings at a time. So, moving on from there, I looked at this year’s starters with at least 100 innings. Then I gathered all their pitch-type run values, and put them each over a per-200-innings denominator. Here are the top 10 pitches for 2017.

Best Pitches of 2017
Pitcher Pitch Value/200
Corey Kluber Slider 35.7
James Paxton Four-seam 30.9
Max Scherzer Slider 30.4
Justin Verlander Four-seam 29.3
Lance McCullers Curveball 28.4
Robbie Ray Four-seam 25.1
Chris Sale Four-seam 25.0
Zack Godley Curveball 24.7
Jason Vargas Changeup 23.9
Chris Archer Slider 23.6
Starting pitchers, minimum 100 innings.

We’ve got Kluber’s breaking ball in first place, by something around five runs per 200 innings. Every pitch on here is good; by definition, really, every pitch on here is good. You see some of the best pitches around. Kluber’s breaking ball is out in the lead. This is probably the strongest evidence for the argument. It’s supported, behind the scenes, by the knowledge that, when batters have swung at Kluber’s breaking ball, they’ve missed half the time.

For additional reference — that table above considers only this season. What if we were to go back to 2008, which is the first year of having this data? Following the same method, and splitting individual pitcher-seasons, here are the best pitches of the decade.

Best Pitches of the Decade
Pitcher Season Pitch Value/200
Corey Kluber 2017 Slider 35.7
Matt Harvey 2013 Four-seam 34.0
Clayton Kershaw 2009 Four-seam 33.6
Clayton Kershaw 2013 Four-seam 33.4
Clayton Kershaw 2016 Slider 32.5
Guillermo Moscoso 2011 Four-seam 32.0
Rich Hill 2016 Curveball 31.5
Joe Ross 2016 Slider 31.0
James Paxton 2017 Four-seam 30.9
Jake Arrieta 2016 Sinker 30.7
Starting pitchers, minimum 100 innings.

Look, I didn’t think I’d be confronted by the name of Guillermo Moscoso today, either. That’s more than a little bit weird. But, you know, whatever — the rest of this checks out. These are very good pitches, the lot of them, and Kluber stands there at the top. One difference is that, unlike most of the other pitches included, Kluber’s pitch isn’t finished being thrown this year. It could either add or lose value over the final few weeks. But Kluber has taken a very good breaking ball and he’s gotten even better about throwing it. He’s been locating it more consistently, and more consistently down. He’s spread it around counts, and hitters have been nearly helpless. Kluber’s generated a career-low rate of swings at pitches in the zone, and a career-high rate of swings at pitches out of the zone. The breaking ball is just one part of his greater repertoire, but it’s the centerpiece, even if it’s thrown less than the sinker.

I don’t know if Kluber throws baseball’s best pitch. I don’t have any way of being truly conclusive about that. The difficult reality is that no individual pitch can ever really be separated from the rest of a given pitcher’s arsenal. Baseball doesn’t like to make things that easy. Let me just say this: Even if we can’t know, we can have inklings. In this case, here, I have an inkling.

Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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5 years ago

Wow that Arrieta 2016 sinker was better than his 2015 slutter? Didn’t really expect to see Arrieta on that list…