The Pitch That Drew Storen’s Slider Became

When the Nationals picked up Jonathan Papelbon, they weren’t doing so to replace Drew Storen, but they knew they’d be giving him a demotion. It didn’t sit real well with Storen, nor did it sit well with a large number of fans, who wondered what Storen did to deserve getting booted from the closer role. Storen is in the middle of probably the best season of his career, with a strikeout rate that’s skyrocketed from last year’s one in five hitters to this year’s one in three. Storen has become a real shutdown reliever, and you generally don’t see those guys losing responsibilities.

But it is possible for Storen and Papelbon to share the later innings. Provided they get along, having both ought to be better than having one or the other, and Papelbon, for his part, was quickly impressed by the younger righty. A tweet that went around:

Jonathan Papelbon: “I was in the shower with Storen, I said ‘can you show me that slider grip tomorrow?’ He was really, really good.”

— Chris Johnson (@masnCJ) July 30, 2015

That slider — we should talk about that slider. Drew Storen has long thrown a slider, but his slider this year is behaving differently, and while you can’t simply chalk his entire improvement up to a tweak of one pitch, it seems to be a major component. Now, some weeks back, Owen already discussed a bit of what was going on. He highlighted some of the changes, and pointed out how successful the pitch is. So, Owen wrote about why the pitch is notable. I want to tell you why it might look familiar.

Compared to last year, Storen’s slider isn’t flying any faster or slower. No speed has been added; no speed has been taken off. However, the pitch now has what you might say is a more exaggerated horizontal plane. Storen’s slider has more lateral break. It’s got a couple inches less drop. More of a Frisbee now, I guess. It seems like a subtle change — we’re talking matters of inches, here — but the slider’s certainly performing better. Looks like Storen might have a better feel for it now.

So, to get to where I’m going, it’s time to call upon pitch comps again. For any of you who haven’t seen this before, I like to compare pitches according to their velocities and movements. This is made easy by the Baseball Prospectus PITCHf/x leaderboards, and for any given pitch, I can calculate a series of comp scores, based on differences and similarities in the components. I find z-score differences in velocity, horizontal movement, and vertical movement, then I add the three numbers together. The lower the total, the better the comp.

You’ve noticed that Jose Fernandez is back, and you’ve noticed that he’s been successful. The return of Jose Fernandez means the return of Jose Fernandez’s breaking ball, arguably the best in the game given how good he is and how often he throws it. In honor of the pitch, I thought I’d try to see if there are any worthwhile active comparisons. So I looked at breaking balls thrown by both starters and relievers, setting a minimum of 50 thrown. When I calculated comp scores, there was a tie for the closest comparison. The two pitchers who throw a pitch most similar to Jose Fernandez’s breaking ball:

• Drew Storen
• Chaz Roe

If I were being more fair, this would be a post about both Storen and Roe, who you might not have ever heard of. But it’s mostly about Storen, even though Roe is having success. I’ll throw in a few Roe details so no one gets hurt. Here’s a table, showing average speed and movements of the three breaking balls:

Pitcher	Velocity	Horizontal Movement	Vertical Movement
Jose Fernandez	83.8	7.9	-1.3
Drew Storen	83.2	8.3	-1.3
Chaz Roe	83.5	8.2	-1.1

It’s obvious why the comp scores are so strong — there’s very little separation in speed. All three pitches break the same, too, and while that doesn’t mean all three pitches are gripped the same or thrown the same, what ultimately matters is what a pitch does, and what these pitches do is more or less alike. In the case of Storen, I doubt he sat down one day and decided he wanted to throw the Fernandez breaking ball, but he changed something, for some reason, and this is the result. Another result: the pitch is super effective. It’s made the biggest difference against right-handed hitters, predictably. Storen’s career strikeout rates against righties:

2010: 23%
2011: 24%
2012: 21%
2013: 22%
2014: 22%
2015: 43%

Here’s an example of what all the pitches look like. Fernandez first:

Now Storen and Roe:

I mean, all right, they all look like low-away breaking balls. When you’re watching a game like that, it’s impossible to spot little details in movement. But the pitches are all almost identical, which a hitter is more likely to notice.

Perhaps they look different out of the hand. I’ve never hit against any of them. And it’s absolutely critical to note that pitch comps have nothing to do with pitch command. From the looks of things, Fernandez commands his breaking ball better than the other guys, which is why the swing rate on Fernandez’s breaking ball is higher. He tends to know where it’s going. But Storen’s breaking ball has a decently high swing rate of its own, and the whiff rate is identical to Fernandez’s. Roe’s is lower, but still high. From Baseball Savant, this is where the breaking balls have gone:

Storen shows what looks like pretty good command. Roe’s looks like an indication of worse command, given how the pitches are spread around, but even he’s got a sub-3 FIP. The breaking ball has been Roe’s most valuable pitch. And Roe has a few inches on the other guys, so maybe that gives him more margin of error. Maybe, with better command, Roe would look unhittable. Jose Fernandez has good command, and he frequently looks unhittable. Drew Storen looks more unhittable than ever.

And that’s owing, in part, to a slider adjustment, that’s left Storen with a breaking ball that looks like perhaps the best breaking ball in the game. Drew Storen, by definition, doesn’t and can’t ever throw Jose Fernandez’s breaking ball. But he’s gotten as close as you can get, throwing his own equivalent that’s left hitters with little chance. It’s no wonder Papelbon wants to know about the grip. When you don’t have easy access to Jose Fernandez, you can settle for the next-best thing.