Stuff+ and The Mountain

I recently joined a men’s 30+ hardball league because, apparently, I love the bitter taste of failure. I felt like a superstar when I left my local sporting goods store with a scroll of a receipt and some fresh gear that would certainly make me, at least, look like I know what I’m doing out there. In my first at-bat, I struck out swinging, missing on a changeup by a country mile. This pitcher knew what he was doing.

He saw me whiff on a heater, threw it again and again as I timed it up and fouled off a few, changed pace and sent me back to the dugout, head down and red-faced. It was hard to time up. I’m serious. Now, replace that 75 MPH heater coming from a former D3 college pitcher with a 102 MPH heater coming from a man they call “The Mountain” and I would have certainly been found in the fetal position on the right side of the batter’s box.

Professional hitters, however, are used to this kind of thing. But, even they struggle. It’s all relative I suppose. Let’s take a look at a hitter, White Sox rookie Oscar Colás, trying to time up Félix Bautista on April 16th:

Colás quickly fouled one off and got the bat on the ball. But, prior to that, he took a ball up and in. The foul ball was his second look at Bautista’s four-seamer and waiting for pitch number three, he sat at 1-1. At this point, Colás saw two fastballs and it couldn’t have hurt to see one more. He took another ball, again the four-seamer, and got ahead in the count, 2-1. Three four-seamers down, Colás must have been feeling like he had Bautista timed. But, wait, doesn’t Bautista have a devastating splitter? That’s what the scouting reports said at least. Maybe that’s coming next? Nope:

Another heater and Colas barely got a hold it, but he was given another opportunity to time it up. Now at 2-2, he was thrown yet another heater and put it in play:

So when oh when does Bautista throw his splitter? At this point in the inning, Bautista threw six straight four-seam fastballs. He had his splitter ready and waiting, but the next batter, Seby Zavala didn’t get to see one. Instead, he was thrown one four-seamer and whiffed, then another that he put in play for a base hit. That means the four-seam count now came to eight in a row and hitters were catching on.

Early this season Orioles broadcasters have continually mentioned that Bautista, who got a late start to spring training due to trouble with his knee and shoulder, just hasn’t yet found the splitter. Stuff+ has given us a new way to look at whether a pitcher has or does not have a certain pitch. Let’s take a look at Bautista’s game-by-game splitter Stuff+ prior to this April 16th outing:

He may not have fully had it in his first few appearances, but the pitch was trending up. For context, the league average Stuff+ on a splitter among all relievers in 2023 currently sits at 103. There were only two games in this early time span where Bautista was below that mark. Prior to this April 16th appearance “The Mountain” started to find his groove with back-to-back appearances above 140. Coming off of two appearances with the splitter working and he hadn’t yet thrown it to a single batter in this game in question. But, just like a brilliant closer does, he waited for the perfect time.

Lenyn Sosa came to bat with two outs, having seen his teammates time up fastballs up in the zone, ready to attack. After a first pitch called strike on a four-seamer, perhaps Sosa was lulled into thinking it was just a fastball kind of day for Bautista. Wrong. The next pitch thrown to Sosa was a totally spiked splitter. In all honesty, it was spiked so hard that Sosa may have not have even identified it as a splitter. The next one, however, was gold:

Bautista then capped off his performance with a swinging strike on an unhittable splitter:

Bringing in the rest of Bautista’s appearances this season (last night’s (5/4) data hasn’t come in yet), we can see that he reached a peak in this April 16th game and in his next appearance on the 18th, but then came back down to earth a bit. What happened on the 29th? Four splitters that looked good, but certainly don’t look 322 Stuff+ good:

Splitter 1
Splitter 2
Splitter 3
Splitter 4

Splitter #1 was a non-competitive pitch. Splitter #2 earned a swinging strike, but it was left up in the zone and seems like it could have been sent for a ride. Splitter #3 was a big miss. Splitter #4 was a really good pitch and an even better take. All together it is unclear why these four splitters read at obscure/outlier levels, but perhaps there’s something going wrong in the data. Regardless, and what does seem clear, is there’s some potential for monitoring individual, put away pitches prior to matchups for both fantasy and real-life players. There’s a lot here that needs to be worked out, mostly creating a rolling average chart, quality checking game-by-game Stuff+ measures, and monitoring game-by-game Stuff+ to see if there’s any connection, not from a performance standpoint, but from a usage standpoint. I would like to answer the question, does an individual pitch’s Stuff+ measurement in the game prior, lead to increased usage in the following? For now, Bautista seems to be finding a devastating pitch and we’ll have to see how he utilizes it going forward.