JABO: When Kershaw Isn’t Exactly Kershaw

Clayton Kershaw is in unfamiliar territory. The three-time Cy Young award winner and consensus best pitcher in baseball finds himself sporting a 4.24 ERA in mid-May, prompting questions about what might be wrong. As we’ll see, luck has largely been unkind to Kershaw, and he’s due for a big regression toward better numbers; however, he hasn’t been the Kershaw we’ve seen for the past two years in one important part of his game, and that has led to some poor results.

Pitchers can’t control everything on the baseball field. After the ball leaves their hand, control is ceded to the batter, the defense, and luck. Also chief among the factors pitchers have little control over: the rate of men they leave on base, the rate of balls in play that go for hits, and the rate of fly balls that go for home runs. Metrics like FIP (Fielding Independent Pitching) and xFIP try to take out a lot of the variability in a pitcher’s stat line influenced by things outside of their control, attempting to measure only what the pitcher is responsible for.

Kershaw has been a victim of some of those factors in 2015. First of all, there’s the rate of balls in play that have actually gone for hits. Here’s a chart of Kershaw’s batting average on balls in play against him over the course of his career compared to league average:

This year batted balls have been finding holes in the infield and gaps in the outfield, something Kershaw doesn’t have much control over. Once those batted balls start finding gloves, they’ll start getting turned into outs more often.

Kershaw’s rate of runners left on base in 2015 has been unlike years past as well. Here’s a chart of the rate at which he’s stranded runners on base over his career compared to league average:

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