Astros Pitching Prospect Spencer Arrighetti Is All in With Analytics

Jonathan Dyer-USA TODAY Sports

Spencer Arrighetti had just thrown a pair of impressive innings when I talked to him following a spring training start in Lakeland, Florida at the end of February. I admittedly didn’t know a ton about the 24-year-old at the time. I was aware that the Houston Astros had named him their 2023 Minor League Pitcher of the Year, and that he’d been taken in the sixth round of the 2021 draft out of the University of Louisiana at Lafayette, but that was mostly it. The only other thing I knew about Arrighetti — this from my perch in the press box — is that he throws a sweeper.

What I learned about the 6-foot-1, 205-pound righty from our postgame conversation is that he is anything but old school with how he approaches his craft. Analytics is Arrighetti’s second language, and when it comes to talking pitching, they are pretty much his first language. Now on the doorstep of the big leagues — he tossed 4 1/3 scoreless innings with the Triple-A Sugar Land Space Cowboys this past Friday — Arrighetti is a bona fide pitching nerd.

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David Laurila: Are you into pitching analytics?

Spencer Arrighetti: “Absolutely. I was taught the data by the Astros, and they obviously know their stuff really well. I love the model that we have. I’ve definitely fallen in love with that aspect, so while the game itself is still more important, I fully acknowledge that we have the ability to train analytically now. We can use data to get better.”

Laurila: What have you learned about yourself since coming to pro ball?

Arrighetti: “I’d summarize it by saying that vertical approach angle is kind of indicative of how a pitch will perform. Fastballs are especially vertical-approach-angle dependent on where you should throw them. I’ve learned about that. I’ve also made an effort to improve vertical approach on my fastball, as well as improve spin axis and spin rates on my other pitches.

“There is also the usage data. I’ve found a really good way to utilize my pitch mix efficiently and effectively. Obviously, we’re always trying to fine tune that — the more you climb the ladder, the more it matters — and at this stage it’s especially important for me to have a concept of what’s going to be good against big league hitters.”

Laurila: Can a pitcher meaningfully improve approach angle, or is more a matter of optimizing what you have?

Arrighetti: “It’s a nice mix of both. You get special athletes who do special things, and there are certain things about a guy you won’t want to change, like his delivery. At the same time, you can absolutely chase it. I think I had a pretty decent vertical approach in college, and after being made aware of it, I made more of an effort to get behind and under the ball.

“We look at hop, and it matters a lot, but I don’t have good hop. My four-seam performs like it has hop, but it actually doesn’t have it. I throw it from… I like to call it ‘throwing it from the basement’ as opposed to throwing from above your head. That’s where you find the vertical approach that is more down to up. So, I think that you can make an effort to refine it. Obviously, you’re not going to take a guy that throws 100 [mph] with a steep vertical approach and tell him, ‘Hey, let’s try to flatten it out a little bit.’ You’re going to tell him, ‘Hey, throw 100. You’re fine.”

Laurila: Hand positioning at release plays into what you’re looking to do…

Arrighetti: “Absolutely. Edgertronic is pretty popular within the data room. You can see exactly where the ball is coming out of your hand, which gives you an idea of the timing of it. You adjust your wrist position based on that; you find that point on the ball where you want to be letting it go.”

Laurila: Have you altered any of your grips as a result?

Arrighetti: “I don’t throw a single pitch the same way that I threw it in college; I actually don’t throw many pitches the same way that I threw them in Low-A. We’ve been really good about finding grips and cues that complement my arm and the way I want to throw the ball. Because of that, I’ve been able to develop an arsenal that I’m really confident in. So yeah, I’ve made a lot of drastic changes — even this offseason. I made a big adjustment with my changeup grip. Grips are great until they’re not, and cues are also great until they’re not. When it’s time to adjust, you adjust. Sometimes the adjustment is big, and that’s OK.”

Laurila: Are any of your grips unique?

Arrighetti: “I would say that they are iterations of other pitches that guys throw really well. In general, the more that analytics have come along, the more we have a good idea of which grip will do what to the ball, and from what slot, horizontal approach, and vertical approach. So, not necessarily unique, but tailored to me.”

Laurila: Do you chase certain movement profiles?

Arrighetti: “Absolutely. I think everybody does.”

Laurila: Some guys claim they don’t…

Arrighetti: “The guys that claim they don’t are most likely guys who don’t love the data. Which is fine. There are big crowds of both. There are guys who think it has no place, and there are guys who think it rules everything. For the most part, I think guys generally fall somewhere in the middle. Personally, I’m probably right in the middle, even with my reverence for the work done in research and development.

“Data is a great tool if you’re open to using it. For the guys that don’t need it, that’s awesome. If you naturally have great shapes, that’s awesome. But I’ve found it very useful to use TrackMan and Edgertronic to fine tune the pitches I’m throwing. Everybody wants more hop on their fastball. Everybody wants more sweep on their sweeper. Everybody wants to throw really nasty stuff. So yeah, I would say I’ve been chasing movement profiles for a little while.”

Laurila: You threw some good sweepers today. Is that your best pitch?

Arrighetti: “I would say it’s my most confident pitch with a right-handed hitter in the box. And there is more to it than how much it moves. The point in space where the ball starts to move matters, as does having the ability to disguise your pitches. But while those things are important, for me, when it’s bigger it’s better. I typically look mostly at the actual amount of movement. Velocity as well, because I’m pretty good at spinning the ball. When I throw at a high spin rate, at high velo, I’m going to get big movement. That’s usually what I’m looking for.”

Laurila: What are the metrics on your sweeper?

Arrighetti: ““I get anywhere from 16 to 26 inches of sweep. I’ve actually gotten reps at 28, and while TrackMan is a little faulty sometimes with its setup, I like to believe that I’m capable of making it move that much. Today it was probably around 18 to 20. You also have to be able to adjust your lines with how much it’s moving. If I’m trying to throw it at a righty’s hip, I want 16, 18, 20. If I’m trying to throw it behind them, bigger than that. It will be closer to 78-79 [mph] when it’s big, and usually 80-82 when it’s smaller.”

Laurila: How do you go about adding or subtracting movement?

Arrighetti: “It’s very intent and leverage-based for me. If I find good leverage with the middle finger, which to me is… I don’t know if you’ve watched Matt Brash throw his, but he’s got one of the best sweepers in baseball. He tries to leverage the ball in his hand with a slight bias towards the side. I’ve found that doing that has helped me a lot. If I can find a seam, have that leverage, and feel the leverage at release, it’s going to be really good.”

Laurila: Do you feel that you comp to Brash?

Arrighetti: “No. If I were to comp myself on that pitch, I’m probably closer to Joe Ryan’s. In terms of sweepers that I love to watch and would like to model mine after, a guy in our org who does really great is Cristian Javier. His is the invisiball sometimes. It’s moving 20 inches with a little bit of induced vertical break at about 80 [mph].”

Laurila: How has your repertoire (four-seamer, sweeper, cutter, curveball, changeup) evolved since you signed?

Arrighetti: “I threw a pretty average four-seam, a really slow loopy curveball, a pretty fringe changeup, and a rifle slider. Really, the only one that’s similar now would be the rifle-spin pitch I throw, which I like to call a cutter.

“My changeup grip has probably changed the most. When I was in college it was a pretty standard circle that didn’t really complement the way I throw. I’m not very good at pronating, so I’ve shifted to more of a low-spin split changeup. I’ve seen a lot of progress with that, because I can keep the supinated wrist and pull through the ball a little bit harder from the top. I don’t really have to worry about turning it over much.”

Laurila: You mentioned spinning the ball well. Is that primarily with your breaking stuff?

Arrighetti: “I spin the fastball well, too. I’ve been up to 2,400 rpm, which is good post-sticky stuff crackdown. When guys were using stick, the really good ones were 2,800, 2,900, 3,000, which is unbelievable. I can spin a breaking ball 3,000, but I’ve never come close with a four-seam. My arm action is pretty whippy, which is usually good for spin rates.”

Laurila: Which of your breaking balls gets the most spin?

Arrighetti: “My curveball, which is more seam efficient than my sweeper. My sweeper is actually very not seam efficient. I’m trying to basically throw a two-seam the other way, if you will. Seam-shifted wake is a hot topic right now. It’s kind of hard to explain, but essentially, I don’t need spin efficiency or spin rate on the slider — but it helps it makes the ball appear white, which is useful.”

Laurila: Any final thoughts?

Arrighetti: “I’ve heard some guys throw around the term fake hop. That’s what we like to call induced vertical break hop. We kind of touched on this earlier. Looking at the TrackMan, my four-seam doesn’t have a lot of hop, but you have to look at the release height and the angle you’re throwing from. For a long time, I didn’t think my four-seam was anything special, and the Astros have made it really clear to me that it’s going to be a great weapon at the upper levels. That’s held true so far. Sometimes the data is a little tricky. You have to look at other numbers that maybe don’t jump off the page.”





David Laurila grew up in Michigan's Upper Peninsula and now writes about baseball from his home in Cambridge, Mass. He authored the Prospectus Q&A series at Baseball Prospectus from December 2006-May 2011 before being claimed off waivers by FanGraphs. He can be followed on Twitter @DavidLaurilaQA.

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hoosonfirstmember since 2024
6 months ago

Really interesting point on his sweeper’s movement. Feels like we’ve heard a few players talk about the tradeoff between spin efficiency and SSW movement. And with how many hitters mention looking for the red of the seams as a way to pick up on different pitches out of the hand, makes sense that Arrighetti’s disguising it. Another reminder that IVB & horizontal break aren’t the be-all, end-all of a good offspeed.

Joe Joe
6 months ago
Reply to  hoosonfirst

I like the spin-based and observed movement figures on the baseball savant pitcher profiles. Not counting cutters, the spin-based figures for Astros pitchers that have come up since about 2019 (especially IFAs) look like closed scissors. The observed movement figure looks like open scissors.The fastballs, curves, sweepers, and changes more or less come out of the same axis (or 180 degrees apart depending if spinning forward or backwards) so they come out of the hand looking like the same pitch. The sliders and changes use SSW to have an observed movement that is much more lateral despite only being slightly different out of the hand than the spin based movements of the curve and fastball , respectively.

Last edited 6 months ago by Joe Joe