Sabermetric Outlook: Hiroki Kuroda

Who saw this coming from Hiroki Kuroda? Before he joined the Yankees, I always thought the Japanese right-hander was underrated, but going from the cavernous Dodger Stadium to homer-happy Yankee Stadium didn’t bode well. Yet somehow, Kuroda has managed to, at least on the surface, improve his numbers and become the most valuable pitcher on the Yankees. But what about under the surface? Is Kuroda actually a better pitcher this year, and is he actually the best on the Yankees? Let’s find out.

If you haven’t done so already, I’d encourage you to first check out the primer that I wrote for this series, which outlines some of the most important statistics that I’ll employ in this post and others. If you’re unfamiliar with sabermetrics, or you’re not sure about a particular statistic I mention, check out that post (if you still don’t understand, please leave a comment below or email me and I’d be happy to help).

Previous players:

As with Sabathia, let’s first look at the sabermetric basics for Kuroda.

Interestingly, Kuroda’s peripherals are pretty much the same this year as his career. He’s giving up more home runs despite a higher groundball percentage, but this is probably a product of Yankee Stadium, as his HR/FB is about average for Yankees pitchers this year.

Even though his peripherals are about the same, Kuroda’s ERA this season is lower than his career number. He has always outpitched his FIP due to a lower-than-average BABIP, but this year, not only is his BABIP even lower, but his left-on-base percentage is very high, leading to an ERA that is much lower than his FIP.

Another way to look at these numbers is by using FanGraphs brand new Fielding Dependant Pitching metrics, which essentially measure the parts of run-prevention not measured by FIP: balls in play and sequencing.

Kuroda, for example, has accrued 3.4 wins through his FIP this year – a respectable number, to be sure, but it doesn’t give him credit for his 3.04 ERA. When we factor in FDP, however, we see that Kuroda has earned 1.1 wins from balls in play (BABIP) and 1.0 wins from sequencing (LOB%). That gives him 5.5 wins if we credit all aspects of run prevention to him, which would make him the 6th most valuable pitcher in baseball.

Read that again. 6th. In baseball. He would be more valuable than Chris Sale, Clayton Kershaw, Matt Cain, Jered Weaver, and countless others, if we evaluated him based on run prevention alone.

But, unfortunately, we probably can’t do that. This isn’t to say that Kuroda definitely doesn’t deserve all the credit, but so far, we don’t know how to figure out how much of that FDP is Kuroda’s doing, and how much is the defense behind him and/or good luck. But let’s try anyway to figure out whether Kuroda deserves credit for those numbers.

The balls in play aspect is the more difficult of the two, mainly because we have no way of knowing how good the defense behind Kuroda has been. We can see how good the Yankees defense overall is, but that tells us very little about the defense when Kuroda pitches. Just like starting pitchers on the same team can often have very different levels of offensive support, so can they have very differing levels of defensive support. Kuroda has given up fewer line drives than usual, which is a good sign. This, along with the fact that he has always put up above average BIP numbers, indicates that the his BABIP is not entirely based on his defense/luck.

The other aspect of Kuroda’s excellent fielding dependent pitching has been his sequencing – that is, when the runners that he allows in fact score. It may be that Kuroda is pitching better with runners on base and in scoring position, in which case we could attribute a lot of his success in that department to him. Let’s take a look:

Wow. Well isn’t that interesting? If I didn’t know better, I would think that Kuroda has done a horrible job this year at preventing runners from scoring. He has struck batters out at a slightly higher rate, but his walk rate and home run rate spike whenever runners are on, especially when they are in scoring position. His BABIP, on the other hand, plummets in these situations. In other words, when runners are on, Kuroda walks way more batters than usual, gives up way more home runs that usual, yet because he is able to limit hits, he has seen success in preventing runners from scoring. Strange.

Unfortunately, the above numbers probably indicate that Kuroda has gotten very lucky in the sequencing department. He is not pitching better when runners are on, but simply getting more help from his defense which is preventing batted balls from turning into hits. I might be tempted to say that Kuroda is just getting weaker contact when runners are on, but that elevated home run rate indicates that batters are hitting the ball just as hard, if not harder, in these situations.

All in all, Kuroda has still had a great year for the Yankees, one that I definitely did not expect. His FIP is about what we would expect based on moving from Dodger Stadium to Yankees Stadium. Much of his success on balls in play can probably be attributed to Kuroda himself since he has shown that skill over his career. However, his ability to strand runners has been more luck than skill, and is unlikely to continue. Still, we can probably expect a 3.50 or so ERA going forward, which is fantastic for a Yankee starter, and will make Kuroda an extremely valuable asset in the playoffs.