What Do the Reds Have in Luis Castillo?

If you’ve watched the Reds recently, you’ve probably noticed that they can score some runs. They’re among the top five or six in the National League no matter which offensive metric you choose for your sorting, and it’s based around a core that may only lose Zack Cozart next year. For this team, then, the future is dependent on pitching — and finding an ace among the many different arms they’ve acquired over the years. Is it possible they have that ace in Luis Castillo?

Castillo came over from the Marlins in the Dan Straily trade, and there’s one thing that pops off his player card right away: he can throw the ball hard. In fact, nobody who’s recorded at least 200 four-seamers this year throws the ball as hard as Luis Castillo.

You might notice something else if you watch that same four-seamer.

To my eyes, that pitch looks pretty straight. Of course, that’s not necessarily an insurmountable problem. Plenty of pitchers have succeeded with straight fastballs. What they usually have though is either have pinpoint command or lots of spin and ride on the pitch. Unfortunately, all of those qualities are fairly difficult to scout with the eyes. Let’s go to the numbers for some help.

Here are Castillo’s various pitches and their percentiles when it comes to movement and velocity and spin, where relevant. These rankings are based on the best available research on what movements are good for each pitch. In each case, a high percentile is a good thing for the pitch. (For more reading on the subject, try the links at the bottom of the table.)

Luis Castillo Pitch Percentiles
Pitch Type Freq Spin Hmov Vmov Velo
Four-Seam 55% 56 82 20 99
Sinker 9% 98 90 99
Change 22% 28 84 90
Slider 14% 77 57
SOURCE: Brooks Baseball

It seems like my eyes might be lying. Castillo’s fastballs have flaws — he doesn’t spin them that well, and he doesn’t have any ride — but when it comes to horizontal movement and velocity, he’s flush. He didn’t have great ground-ball rates in the minors, but his current 58% ground-ball rate is believable, given the relationship between horizontal movement, velocity, and ground-ball rate.

But whiffs are the ticket, and that’s where his mediocre minor-league numbers might be a little bit scarier. This changeup is obviously his best pitch, with a great velocity gap off of his fastball and sink that should make it a great pitch for whiffs, even without much fade.

As for the slider… sliders are tough to study. There are all sorts of different ways to have a good slider, but it seems that the attributes which most strongly correlate with success are velocity and drop, which is also what the research on curveballs suggests.

Castillo doesn’t stand out in either of those dimensions, especially given that he’s achieving that above-average drop with below-average velocity — balls drop more at lower speeds, after all. So maybe it’s no surprise that the whiff rate on this pitch is currently just a notch below average:

In sum, we’ve got a flame-throwing righty with one plus secondary pitch and another average one. If we count the fastball as a plus, then we get to compare him to pitchers like Michael Fulmer and Luis Severino, two other righties with similar profiles.

But will the flaws on the fastball sap him of that sort of upside? He might be stuck between his two fastballs. The plus movement on the sinker would almost certainly make it a better primary pitch. Watch it and be mesmerized:

But Castillo’s already a little wild and two-seamers, because of the extra moment, are typically more difficult to command. That one looks impossible to command. Could Castillo be successful with it anyway if he put it in the right places?

That’s a heat map of Castillo’s current sinker placement. Right now, he’s probably not using it much to get called strikes, since he throws five four-seamers for every one sinker. So we’re looking at that location at the bottom of the zone to right-handers: could he move that hot zone up so that it’s grabbing more of the strike zone? If so, with that velocity and movement, he’d get the unholy trio of whiffs, called strikes, and ground balls.

Fiddling with the fastball mix and establishing better command of the sinker — that may be the only thing between Luis Castillo and ace-hood.

Thanks to Jeff Zimmerman for the GIFs.

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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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Ryan DC
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Ryan DC

So is “ride” on a 4-seam fastball the same thing as “rise”? Are those both just words for “less drop than a hypothetical spin-less fastball”?