• Cleveland Indians ace Corey Kluber was uncharacteristically bad before going on the DL. Now that he's back he's pitching better ... and smarter.
By Michael Beller
June 19, 2017

Corey Kluber’s first six starts of the season, the six he made before hitting the DL with a back injury, were anything but vintage for the Indians ace. He had a 5.06 ERA and 1.37 WHIP in 37 1/3 innings, with hitters carrying a .262/.323/.476 line against him. That’s not what anyone expects to see from Kluber, so it made sense that he went to the DL. If his back were the root of his issues, then he’d be able to heal and return to his usual form after a short stint on the shelf.

That logic was right. Kluber has made three starts since returning from the DL, allowing five runs on 13 hits with 28 strikeouts against four walks in 21 innings. He has fanned at least eight batters in all three outings, and has reached double digits in two of them. In Kluber’s most recent start, a 10-whiff, 7-inning gem against the Dodgers, he became the fastest pitcher in Indians history to reach 1,000 career strikeouts, doing so in 148 games.

The results have been a welcome change from earlier in the season, but they aren’t all that interesting. “Ace returns to dominant form” isn’t exactly headline that will make anyone do a double-take. What is intriguing, however, is Kluber’s path to those results; the pitch mix he has deployed that should have baseball observers looking on with furrowed brows.

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Statcast and BaseballSavant.com, which become more indispensable by the day, allow users to look at data before or after a certain date. That gives us the ability to isolate Kluber’s six starts before he went on the DL from the three he has made since returning. The following pie charts reflect that. The first documents Kluber’s first six starts and the second one his most recent three.

The first element that jumps out is the curveball, which has had a much larger presence since Kluber returned from his back injury. Kluber is also throwing his cutter a bit more, but the change isn’t as dramatic. The slider and cutter are close to the same pitch; the difference comes in the velocity and the break. The harder version, which has less break but more zip, is the cutter. The slower version, which breaks far more sharply, is the slider. They are largely the same offering, though, and the difference in the cutter usage can likely be explained by coding issues. Still, even if we lump the cutter and slider together by adding their usage rates, that one offering has jumped to 25.6% after the injury from 18.9% before it.

The curve and cutter/slider have eaten significantly into Kluber’s sinker usage, which was at 40.6% before the injury, but has fallen all the way to 22.1% over his last three starts. Kluber’s sinker isn’t going away, but he’s relying on it less. That said, he won’t turn his back on the pitch when it is this good. Just look at this pitch to Dodgers slugger Cody Bellinger.

That’s filthy. Kluber’s sinker is a foundational pitch that is the backbone of his arsenal, and its reduction in recent starts can likely be explained primarily by variance. He threw it more than two-fifths of the time from 2013 through 2016, and that’s exactly where he was to start this year. Kluber’s sinker usage rate will bounce back in due time.

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Still, it’s worth looking at the curveball, given its importance during his best run of the 2017 season. Kluber has thrown his curve 93 times over his last three starts and produced a remarkable 26 whiffs with it, good for a swinging-strike rate of 28%. Twenty more have been called strikes, while hitters have fouled off 12 of Kluber’s curves. That means 62.4% of Kluber’s curves have produced a strike of some sort since he has returned from the DL. Hitters are 4-for-12 when putting it in play, but who cares about a .333 average in a small sample when you’re getting a strike more than three-fifths of the time? Oh, and just for the record, three of the hits were singles, and two of those had exit velocities less than 65 mph. No one is successfully hitting this pitch.

If you’ve read any of these columns this year, you know what a sucker I am for a pitcher who can throw a nasty breaking pitch for a strike. Chase pitches are one thing, and every good breaking ball should be able to produce outs on pitches outside the zone. Kluber shows that off here, getting Avisail Garcia to fail at a curve in the dirt down and away.

Any good pitcher can get hitters to whiff at breaking balls out of the zone when they’re ahead in the count. The great ones can throw their breaking pitches for strikes. Kluber has been doing just that with the curve repeatedly this month. Look, here he is doing it against Ryon Healy.

And here he is freezing Matt Davidson.

That Davidson curve is particularly knee-buckling. Few hitters are going to sit curveball in an 0–2 count, and fewer still will be capable of fighting it off should they be lucky enough to identify it. Kluber is so in Davidson’s head, that he knows all he needs here is a pitch in the zone, and he’s out of the inning. Of course, you need a curveball as good as is, and an unyielding confidence in it, to throw that pitch, even way ahead in the count. This is what makes Kluber so special.

Before wrapping this up, let’s bring back Cody Bellinger. We saw him earlier when Kluber snuck that beautiful sinker in the front door for strike three. The following was his subsequent plate appearance. Kluber showed him three different pitches—his four-seamer, sinker and cutter—to get to a 1–2 count. You can see the locations and flight paths of those pitches here.

At this point, Bellinger is set up for just about any pitch Kluber wants to throw and, remember, he just burned with the sinker in his previous at-bat. Kluber goes to the curve, which Bellinger had seen just once all night, and gets him to swing over the top of it.

The beautiful thing about that pitch, other than the setup and the offering itself, is that if Bellinger doesn’t swing, he’s still walking back to the dugout with his bat in his hands after taking strike three. This is Kluber at his best, the vintage he was missing during his first six starts. It’s safe to say he’s back.

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