I’ve become atypically interested in Clayton Kershaw’s second arm slot. You know, the one where he drops from being so over the top. It is, apparently, Kershaw’s natural arm angle, but it’s not the one he took to the majors. It’s not something he ever used as a Dodger until he felt sufficiently inspired by teammate Rich Hill. Hill also drops down from time to time, and although Kershaw doesn’t drop down by so much, it’s interesting to see him messing around in the first place. Clayton Kershaw is, after all, the best starting pitcher in the world.

Players are always attempting some kind of tweak. They’re forever in search of some kind of leg up. Chris Taylor made the tweak he needed to make in order to become a quality major-league hitter. What interests me about someone like Kershaw is — a player like Taylor is strongly incentivized to improve. His career literally depended on it. Kershaw hasn’t needed to improve. Kershaw has only ever struggled relative to himself. Kershaw didn’t need to start changing up his arm angle. He wanted to try it anyway. Kershaw experimented for the sake of taking his opponent by surprise.

I love that drive that he has. It’s probably suggestive of how Kershaw got so good at all. He doesn’t want anyone to get too comfortable. To bring this all home: Kershaw has unveiled a couple surprises. Late last year, he suddenly started dropping down. And this year, one month ago, Kershaw threw a curveball. It was a special curveball.

This is Daren Willman. You know him for being the creator of Baseball Savant. Great site, great dude. Willman makes for a good follow on Twitter, and every now and then, I’ve seen him tweet out some variation of a Kershaw fun fact. Here is how Kershaw has used his curveball, over the course of his career, broken down by count.

The Kershaw curveball is a famous one. Vin Scully gave it a nickname all the way back in that one spring training. The curveball, in large part, is what got Kershaw to the bigs, and it’s a pitch he continues to trust. And yet, there’s something odd about the usage pattern. Kershaw throws his fastball in any count. He throws his slider in any count. He pretty much only ever throws his curveball when he’s even in the count or ahead.

It doesn’t seem optimal. You’d think that, when you’re a pitcher with three good pitches, you wouldn’t want to ever just completely ignore one. It’s a very uniquely Kershavian thing to do, but, because this is Clayton Kershaw, no one could ever give him too much grief. Obviously, whatever he’s doing has worked. In the big picture, Kershaw’s been the best. Can’t criticize the best for doing what he does, however he does it.

There’s no actual definition of being ahead in the count or behind. There are, in all, 12 possible counts. By the loosest definition, a pitcher would be behind in the count when there are more balls than strikes. To this, I’d like to add one condition: I don’t personally think a pitcher is behind when the count is full. I don’t think a pitcher can be behind when there are two strikes. So we’d be left with five counts that qualify: 3-and-0, 3-and-1, 2-and-0, 2-and-1, and 1-and-0. All of these counts are hitter-friendly. The numbers bear it out.

Using both Baseball Savant and Brooks Baseball, I did a lot of digging. When the count’s been 3-and-0, Kershaw has never thrown a curveball in his career. When the count’s been 3-and-1, Kershaw hasn’t thrown a curveball since 2008. When the count’s been 2-and-0, Kershaw hasn’t thrown a curveball since 2008. When the count’s been 2-and-1, Kershaw hasn’t thrown a curveball since 2009. And when the count’s been 1-and-0, Kershaw hadn’t thrown a curveball since April 11, 2011. He threw that curve to Pablo Sandoval. Then a whole bunch of nothing. Then, a curve. A curve in the year 2017.

There was, in 2012, this weird-ass blip.

That’s certainly different, but it’s not the classic Kershaw curve. Doesn’t count. Interesting! But, it doesn’t count. To put it all together, here’s a bar graph. Here are Kershaw’s total curveball counts when behind.

As the slider emerged, the curveball faded. Not out of the picture entirely, but out of the picture when Kershaw needed to battle back. Not a single behind-in-the-count curve in 2012. Not a single behind-in-the-count curve in 2013. Not a single one of them in 2014, or 2015, or 2016. And then, in 2017, one. And that one curveball occurred in the playoffs.

We’re going back to October 6. We’re going back to when there was still baseball, and the Dodgers were alive, and they were playing the Diamondbacks. The previous curveball in question was thrown in April of 2011. This one was thrown in October of 2017. That covered a span of well more than 200 Kershaw outings. It covered a span of well more than 4,000 Kershaw pitches when behind in the count. All of those pitches, and not one curve. And in the NLDS, Kershaw looked in at Yasmani Grandal, and Grandal didn’t ask him to throw a curve. Kershaw was in a 1-and-0 count, facing J.D. Martinez. Whatever Grandal initially called, Kershaw shook him off.

I don’t know how to explain it. Kershaw didn’t misread the signal. Kershaw and Grandal didn’t get crossed up. I spent annoyingly long staring at game video, and the call was clearly there, in plain view of the camera. After Kershaw shook his head a couple times, Grandal signaled for the curveball. Kershaw began his wind-up. I don’t know what it was. I don’t know why Kershaw wanted to go away from his pattern so suddenly. Maybe he just had a feeling. Maybe it was the confidence of pitching in a six-run game. Maybe, for some reason, Kershaw was just blissfully unaware of the circumstances. Kershaw, again, hadn’t thrown a curveball when behind in the count over some thousands of consecutive opportunities. For some reason or another, Kershaw decided to spin one in. It would be, objectively, one of the more surprising pitches imaginable. Martinez couldn’t have known it, but with him as the guinea pig, Kershaw was going to try to take advantage of more than five years of selective curveball avoidance.

Kershaw went into his wind-up. I don’t know how he was feeling. I’m not sure if he was feeling nervous, and I’m not sure if he was feeling excited. I’m not sure if he was feeling anything at all. Martinez was about to get ambushed. Maybe Kershaw just wanted to have a little of his own kind of fun. His arm went back. His arm went forward.

Baseball will never, ever, ever make sense. It is the worst thing about this dumb sport, and by far its greatest quality.