Jose Fernandez Has Two Breaking Balls

Sometimes you just have to ask. Different systems have different answers for the pitching mix that Jose Fernandez brings to the mound each game. So I did ask him. I said, “Do you consider your breaking ball a slider or a curve?” And the Marlins’ righty said, “I got both. I can throw both. I trust them both equally.” It was a group scrum, not the time for a real in-depth thing, but just knowing there are two there can set us on a path.

For one, we can visualize those two pitches. Look at the graph below. Check out all of his breaking balls by movement, velocity (color) and batter handedness (shape). Check out the harder, tighter one he uses against right-handers (squares) and the bigger, softer, loopier one he uses against lefties (circles). You can even filter by handedness to see how the blob changes.

Next, let’s define the two pitches. Using K-Means clustering, Matt Dennewitz of helped find the horizontal and vertical movements that define Fernandez’s slider and curve. The results of those calculations allow us to see what these two pitches do. (Note: in the table below, % vs L means, for example, that 52% of all curves were used against lefties.)

Jose Fernandez’s Two Breaking Balls
Pitch Velocity Horizontal Vertical % vs L Whiff%
Slider 83.1 7.2 -0.3 34% 22.3%
Curve 81.7 10.9 -2.8 52% 17.3%

In the beer world, it’s well known that you can game the competitions by finding a lesser-known style in which to submit your beer. Since curves have such a lower average whiff rate than sliders (10.5% to 14.4%), Fernandez has long shown up in my database queries as having the second-best curve in baseball by whiff rates.

What’s more correct, after seeing the two pitchers split out like this, is that he possesses the 12th- or 13th-best curve in baseball’s starting pitchers… and also the 11th-best slider. It doesn’t sound as impressive, perhaps, but Carlos Carrasco is the only other starting pitcher who can boast top-15 whiff rates on two breaking balls. It’s impressive, in a different way.

Let’s look at the pitches separately now.

First the curve, thrown here to a lefty for strike three. He bounces it, and it’s really, really big. It leaves his hand at 82 mph.

Now the slider, thrown to a righty for strike three. It’s tighter. And faster. It leaves his hand at 86 mph.

Maybe these two pitches look alike, but we have to return to what Fernandez said — he has two. His own claims are further supported by the heat maps and the usage rates.

And that’s why it’s meaningful. Fernandez doesn’t throw his changeup a whole bunch. Most systems agree that he throws it about 10% of the time, and it gets the worst whiff rates among his three secondary pitches. More than 90% of the time he throws the change, it’s to a lefty, so it’s a bit predictable.

But that matters a whole lot less if he has another weapon against lefties. Perhaps the fact that he has two breaking balls is the reason that Fernandez has struck out more than a quarter of the lefties he’s seen. And maybe the fact that he goes to the bigger, slower “curveball” more against lefties is part of the reason that his walk rate against lefties is nearly double.

Maybe it’s not meaningful. You’ll hear his breaking ball described as such, or as a slurve, and referred to as one pitch. And if you look too long at the images above, you might even agree that those two look very similar.

But those subtle differences make each of his breaking balls more effective against batters of different handedness. Max Marchi’s work on platoon splits — which broke curve balls into three categories — found that the deeper, slower, bigger curve balls have reverse splits. They were more effective against opposite-handed hitters than same-handed hitters.

So yeah, Jose Fernandez has two breaking balls. Don’t get too comfortable if you’re a lefty.

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With a phone full of pictures of pitchers' fingers, strange beers, and his two toddler sons, Eno Sarris can be found at the ballpark or a brewery most days. Read him here, writing about the A's or Giants at The Athletic, or about beer at October. Follow him on Twitter @enosarris if you can handle the sandwiches and inanity.

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