It’s Time to Stop Ignoring the Kershaw Home Runs

Clayton Kershaw is the best pitcher of his generation. He is a six-time All-Star and a three-time Cy Young winner. The Los Angeles Dodgers ace won’t turn 30 until next season, but he has already accumulated over 2,000 strikeouts and 135 wins. So, when we see Kershaw falter a little bit for a short period of time, it is justified that the struggles are written off as nothing. That’s what was done earlier this year, but, 14 starts into 2017, he has a problem that isn’t going away. And it’s time to really investigate the issue.

Kershaw has given up at least one home run in his last four starts, and is just three long balls away from tying his career-high 16 home runs allowed in 2012. Those 16 came in 33 starts. Let’s compare his HR/9 and HR/FB for each season:

Season	HR/9	HR/FB
2008	0.92	11.6%
2009	0.37	4.1%
2010	0.57	5.8%
2011	0.58	6.7%
2012	0.63	8.1%
2013	0.42	5.8%
2014	0.41	6.6%
2015	0.58	10.1%
2016	0.48	7.5%
2017	1.21	15.9%

Both would easily be career highs, and aside from his rookie year in 2008, his current HR/9 of 1.21 would nearly double the next worst.

It’s not like this issue has destroyed him or trickled down into the rest of his game — he is still running a 2.23 ERA. His 23.8% K-BB% isn’t quite what it’s been the last few seasons, but it is still better than his career average. Kershaw has actually still been great, but he is held to a different standard than any other pitcher in the league. He just hasn’t been Kershaw great. So what’s behind the home runs?

Well, we are dealing with Kershaw here, so the first thing to investigate is whether he has had a little bad luck. Maybe a few balls that normally shouldn’t clear the fence did…

But that’s not the case, and that explanation is actually a lot further off than one might expect. Kershaw’s allowed home runs have been hammered. The average exit velocity on them is 105.5 mph, which ranks in the 12th percentile for pitchers who have allowed at least five home runs. Not a single one has been hit below 100 mph, and only two of the home runs had a home-run probability lower than 50%. One of those two is a home run 37% of the time, but it’s usually not an out, either. Similar balls in play to that home run have an .800 average. The other one under 50% is a home run 49% of the time. So, clearly he’s not suffering from bad luck, and it’s actually a little troubling how little luck has gone into the homers.

Strangely, while the home runs have been crushed, Kershaw isn’t giving up more hard contact overall. His hard-contact rate is nearly identical to last season’s, and he is actually sporting a career high in soft-contact rate. Hitters are turning on specific pitches, not hitting him harder overall.

The specific pitch they’re turning on is, surprisingly, his fastball. From 2011 (when Kershaw won his first Cy Young) to 2016, Kershaw’s fastball had a whopping 148.6 run value. That easily ranked first, and the next closest in that time frame was his teammate, Kenley Jansen, at 97.8. His fastball simply dominated guys. And while pitch values are not the most perfect metric to use, there is something to be said that his fastball ranks only 20th in run value in 2017. Yes, 20th out of 85 is far from poor, but remember who we are talking about here.

In that 2011-2016 time frame, Kershaw gave up 44 home runs on his fastball. 14 of those came on pitches that landed arm side of the plate and in the middle third. That was seven more than any other zone. That trend hasn’t changed this season, as half of his eight home runs allowed on fastballs have come in that zone. Obviously some of that is due to the frequency that he throws his fastballs there, but hitters still like to club his fastball there more than any other areas.

So, that zone, along with the middle of the plate (like with any pitcher), are the danger zones for Kershaw’s fastball. Well, look at Kershaw’s fastball location from 2011-2016. Kershaw likes to elevate his fastball on the outer third, so making the occasional mistake and bringing it too low is understandable. But, now, look at Kershaw’s fastball location this season. Yikes. Kershaw is throwing his fastball most often right in the middle of his weak zones.

The pitch is good enough that, even with the poor location this season, it’s still a great pitch. The average exit velocity on his fastball is 85.0 mph in 2017, compared to 84.8 mph in 2015-2016. Guys aren’t consistently hitting it any harder than they usually do. The issue is Kershaw is making more mistakes. In 2011-2016, hitters had a barrel (balls in play with at least .500 average, 1.500 slugging) rate of .11% on his fastball. In 2017, that number has skyrocketed to .94%. Kershaw is leaving it in the sweet spot of the zone too often.

The fly-ball rate on the pitch is also way up to 35.2% this season, which is much greater than recent years. We all know about the launch-angle obsession and how guys are trying to lift the ball out of the park more. If you hit the ball higher, it’s more likely to sail over the wall. Well, that is exactly what’s happening to Kershaw. The overall effectiveness of trying to raise one’s launch angle is yet to be determined, but it clearly leads to more home runs. It’s no surprise that if Kershaw is allowing more balls in the air, he’s allowing more home runs.

Kershaw seems to have lost some command on his fastball, and hitters are starting to tee off on it a little more than usual. If anyone could recover from this, it would be Kershaw. Obviously, with the way he is still pitching, the home runs are not a death sentence. But with the way these balls have been crushed, the issue is worrisome and it hasn’t been shrinking as the sample size increases.