Just How Good Is Clayton Kershaw?

The Houston Astros will be facing the best pitcher in baseball on Tuesday night. Ian York takes a close look at what the Los Angeles DodgersClayton Kershaw throws and how his pitches move. 

Clayton Kershaw is the best pitcher on the planet, and it’s not particularly close. In the last seven years, he has led the National League in ERA five times, in WHIP four times, and won three Cy Young awards. In 2017, he tied for the lead in wins with an 18-4 record, in spite of missing all of August with a back injury, and ESPN ranks him second in the 2017 Cy Young stakes, barely behind his teammate Kenley Jansen.

His only real sign of weakness this year has been a platoon split that is unusual for him. Although in previous years he has handled left-handed batters just about as well as righties, in 2017 lefties put up a .734 OPS against him – not terrible, but un-Kershaw-like, and .435 points higher than LHB did against him in 2016.

What he throws. Kershaw has three main pitches: four-seam fastball (“FF”), slider (“SL”), and curve (“CU”). He also occasionally throws a changeup (“CH”) and a second fastball, presumably a two-seam fastball (“FT”) that has much more horizontal movement and a little more velocity than his four-seam.




Kershaw is all about the vertical movement on his pitches. With the exception of his very rare two-seam fastball, his pitches have very little horizontal movement, but have huge vertical movement compared to the average pitcher. His fastballs have great “rise“, and his curve has excellent drop. Here is his four-seam fastball, in red, compared to other left-handed pitchers who threw at least 100 fastballs, showing its horizontal movement (left chart) and vertical movement (right):

Here is his curve, which has negative vertical movement (i.e. drop), and almost no horizontal movement:

And here is how they compare side by side. This animation shows a fastball Kershaw threw on June 19 to Gavin Cecchini; the curve is one he threw to A.J. Pollock on July 4. Both pitches were fouled off.

The solid lines represent the path these pitches would have traveled under the influence of gravity alone, in a vacuum. The curve would have hit the bottom part of the strike zone; it ended up just inches below the zone. The fastball was on a trajectory to bounce several feet in front of the plate; its spin pulled it up to be easily within the zone. Neither moved more than a few inches horizontally.

Pitch usage and trends. Kershaw changes his pitch usage significantly depending on the situation. Overall, his fastball (46.3% of pitches) and slider (34.7%) are his most common pitches, with his curve (16.6%) well behind them. When he is ahead in the count, though, he is much more likely to use his curve (31.7%). When behind, he simply doesn’t throw a curve at all (0.2%), using his slider instead (48.3%). Right-handed batters are also more likely to see sliders than left-handed batters (35.6 vs 28.3%). The changeup and two-seam fastball are both very rare (1.2% and 1.1% of pitches respectively).

He was fairly consistent with his pitch repertoire over the course of the 2017 season, and didn’t particularly change pitch usage or velocity after his return from the DL (marked with a blue line) or in the post-season (after the green line). Interestingly, almost all of his two-seam fastballs were thrown over seven consecutive games in May and June, after which he stopped using it until the post-season.

Pitch value. Unusually for Kershaw, his fastball was actually slightly less effective than the average, as measured by total bases yielded per 100 pitches. His slider was better than average overall, but left-handed batters (relatively) feasted on it, explaining his platoon split for the season. All his pitches, however, were much better than average in terms of balls per 100 pitches.

Pitch location. Many pitchers with good control place their pitches in a tight cluster in one part of the strike zone. Kershaw does this, more or less, with his slider, which targets the bottom edge of the strike zone, but his fastball and (to a lesser extent) curve don’t show this pattern. Instead, Kershaw uses the whole strike zone for those pitches, but rarely leaves the strike zone. It’s that combination of unpredictability with deceptive pitch movement that makes the best pitcher in baseball.

Follow Ian on Twitter @iayork

Feature image courtesy of nypost.com

About Ian York 208 Articles
Ian is an immunologist and virologist who lives in Atlanta with his wife and two sons. Most of his time is spent driving his kids to baseball and soccer games, during which he indoctrinates his children on the glories of Pedro Martinez, the many virtues of the Montreal Expos, and other important information.

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