clock menu more-arrow no yes mobile

Filed under:

How unlucky has Clayton Kershaw been in 2015? Looking at his year with StatCast exit velocity readings

Kirby Lee-USA TODAY Sports

Clayton Kershaw's ERA has jumped up about 1.5 runs from last year, from 1.77 to 3.20, which isn't what a fantasy owner had in mind when drafting him in the first round this year. xFIP indicates that Kershaw is essentially performing the same as last year: his xFIP differential between 2014 and 2015 is just 0.02 (2.08 to 2.10). I don't like just pointing to xFIP and calling it a day because not all fly balls are created equal. A pitcher who gives up fly balls at an average exit speed in the 90+ mph range is probably going to be more likely to have more of those go for home runs than a pitcher who gives up fly balls at an average exit speed in the lower 80s. I'm not aware of any (public) baseball studies confirming this to be absolute fact, but it seems logical. To give some data to support that opinion, only two home runs this year were clocked at less than 90 mph by Greg Rybarczyk's

Looking at Kershaw's average exit velocity on opponent's batted balls via statcast data from Daren Willman's excellent Baseball Savant, it looks like he's been very unlucky on fly balls this year, as xFIP would indicate, but probably even moreso than xFIP shows. Kershaw's average exit velocity on all his batted balls is lowest in baseball at 83.71 mph (min. 100 BIP), and his average exit velocity on fly balls is 2nd lowest at 84.96 mph. If we include pop ups into the fly ball percentage, Kershaw's average exit velocity on fly balls drops to 79.91 mph, which is lowest in baseball by 3 mph; there isn't a close second.

Kershaw has consistently outperfomed his xFIP throughout his career, likely because of this very reason. More softly hit fly balls than average should lead to less of those fly balls going for home runs than the average, right? It makes sense. His career HR/FB% is 7.1%, including this year, well below the average of about 10%.

I am nowhere near sophisticated with baseball data, just a humble fantasy owner, so there could be errors in my process. But I feel confident based on what I see that Kershaw has no business running even an average HR/FB% this year, let alone one towards the bottom of the league (17.2%). A normalization to that ratio would provide a gigantic boost in run prevention, vintage Kershaw type run prevention.


Kershaw faces the lousy New York Mets offense this Friday at home, and it's a good idea to keep hammering him into lineups the rest of the year because of a strong chance for a massive turnaround in run prevention based on the statcast data. His results on fly balls has kept his price down from where it would be with a vintage Kershaw ERA, and a fantasy owner can take advantage of this.

You can follow me on twitter @TimFinn521