What’s wrong with Clayton Kershaw?

It’s a question I’ve started to hear recently. At one level, you can understand why people are asking it. Kershaw is currently 2-3 on the season with a 4.32 ERA. If you can remember back to last season Kershaw was 21-3 with a 1.77 ERA. Those numbers still make me shake my head — Kershaw has already lost as many games as he did last season and his ERA is almost two and a half runs higher. At that level you can understand the concern.

But should we be concerned about Clayton Kershaw? Kershaw’s 2015 season provides a perfect opportunity to introduce baseball fans to the need for DIPS (defensive independent pitching statistics). On a recent episode of Effectively Wild, Sam Miller of Baseball Prospectus noted that DIPS was one of the most important contributions of sabermetrics to the baseball community. I’ve mentioned in previous posts that I’m fairly new to sabermetrics and I’m still learning my way around many of these new statistics. However, let me show you how DIPS can give you a different perspective on pitcher performance, and in this instance, Kershaw.

In Travis Sawchik’s new book, Big Data Baseball, he gives a helpful crash course on DIPS (pg. 73-81). If you haven’t picked it up yet you really should. Even if you’re not a Pirates fan it’s a great introduction to the practical implication of sabermetrics on baseball. He attributes the beginning of DIPS to an article written by Voros McCracken for Baseball Prospectus, “How Much Control Do Hurlers Have?” Here are the highlights of McCracken’s article (as summarized in Sawchik):

  • Hits allowed are not a particularly meaningful statistic in the evaluation of pitchers
  • What do pitchers independently have control of? Strikeout rate, walk rate, home runs allowed, and hit batsmen
  • If hits allowed are largely dependent on the defense behind the pitcher, then ERA is an insufficient way of evaluating a pitcher
  • Regardless of era, major league hitters typically have around a .300 batting average on balls in play (BABIP)

In essence McCracken was arguing, “if a ball was put into play…a pitcher’s influence over whether a batted ball was converted into an out or a hit was largely subject to the ability and placement of the defenders behind them, while also tied to the dimensions of the ballpark they pitched in” (Sawchik, 74).

McCracken’s research led to the introduction of a new statistic, FIP (Fielding Independent Pitching). This stat, “measures what a player’s ERA would look like over a given period of time if the pitcher were to have experienced league average results on balls in play and league average timing” (Fangraphs Library). If you want the nitty gritty details on FIP click the Fangraphs Library link.

So how does Clayton Kershaw’s 2014 and 2015 compare when we look at statistics that he can control (league average stats are in parentheses). This was written prior to Kershaw’s starts on Tuesday night.

2014

2015

K% 31.9 (20.4) 30 (20.1)
BB% 4.1 (7.6) 6.6 (7.8)
HR/9 0.41 (0.86) 0.93 (0.95)
Velocity (Fastball) 92.9 93.4
FIP 1.81 (3.74) 2.90 (3.91)
BABIP .278 (.295) .342 (.293)

 

Has Clayton Kershaw been as good this season as he was last season? Not quite, but it would be impossible for almost any pitcher to live up that standard. However, has he been as bad as some have suggested? His K% is right in line with last season. He’s walking a few more hitters then last year. His HR/9 numbers are up, but that number is still around league average. All of those statistics we just mentioned are still better then league average.

There are two statistics that really stand out though. First, Kershaw’s BABIP this season is .342. That’s well above league average. What does this mean? So far Kershaw has been fairly unlucky on balls that have been put in play off of him. Again this is something he has no control over, and for whatever reason more hits are falling in then would be expected. You should expect this to come back closer to .300 over time. On the other hand he had better luck then would be expected in 2014 with his .278 BABIP.

With that number in mind we can take a look at his FIP this season. His 2.90 FIP is still well below league average. That’s good enough for 13th best in baseball. If Kershaw was experiencing “league average results” on balls in play then his ERA would look much different this season.

Let me conclude by saying this. If you look at Kershaw’s traditional statistics you would conclude he is “struggling some this season” as an ESPN commentator noted prior to the Dodgers game tonight. However, if you look at the statistics that measure what Clayton Kershaw can independently control then you come away with a much different picture. What you have is a pitcher who is still well above league average who has run into some bad luck this season. No he’s not having his historic 2014, but he’s still been really good. Maybe we shouldn’t be asking “What’s wrong with Clayton Kershaw?” Rather, sabermetrics has helped us see that we should be asking, “What’s wrong with W-L record and ERA as the end all be all in pitcher evaluations?”

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One Response to “Clayton Kershaw and the Need for DIPS”

  1. jared

    Eric I wonder if the research you cite above figures in a batted ball’s trajectory. This would seem to be something a pitcher could influence if not specifically “control”. For instance, K-rate is millimeters different from trajectory influence. A batter swings over, behind, above a given pitch resulting in a swing and miss, while the same pitch might be put in play but with such a trajectory that it has a greater chance of becoming an out. The BABIP statistic is used with a near spousal connection to “luck” (the irony of that advanced metric and ancient quality should be lost on exactly no one), but baseball fans and students alike realize that balls hit with certain trajectories and exiting or off the bat speed are more likely to result in hits.
    All this to say, you’re probably right–ERA and W-L numbers are not exclusively definitive stats, but perhaps they shouldn’t be jettisoned quite yet.

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