Spencer Arrighetti is Poised for a Breakout in 25'
Analyzing Spencer Arrighetti’s Strengths and the Key Adjustments for a 2025 Breakout
Opening
With baseball getting closer and closer with every sleep, I think it's a good time to start a new series about potential breakout players in 25’. To start it off, I wait to take a look at Spencer Arrighetti in particular. In 2024, Arrightti posted rather average results with a 4.53 ERA, 4.05 xERA, and 4.18 FIP, but had dominant stretches with a 1.95 ERA and a 2.80 FIP in August, earning him the Rookie of the Month award! During that stretch, Arrighetti became the first AL Rookie to put up back-to-back 12-strikeout outings while also carrying a no-hit bid into the 8th against the Phillies, where he also racked up another 10 strikeouts.
Obviously, there is potential with Arrighetti; the question is: How will the Astros muster this out of him? I feel like it's a combination of playing into his low release height to his advantage as well as emphasizing the utilization of his breaking pitches more. With these possible adjustments, I think Arrighetti can be a real breakout candidate for the 25’ season and on for this young Astros staff.
Delivery Characteristics
Before getting into why I believe Arrighetti is a major breakout candidate, let's get a feel for his delivery characteristics. First off, Arrighetti strikes me as a bicep-dominant pitcher with a slight bias towards pronation. The reason I say this is because of his 95.1% 4-seam spin with the ability to produce multiple breaking ball shapes. It's important, though, to view this pronation/supination bias on a spectrum. What I mean by this is that Arrighetti isn't limited to the typical pronator mix of a 4-seam, changeup, and a gyro slider just because he's a “pronator.” Some pitchers, like Arrighetti, are able to achieve supination-based pitches because of their other biases, and for Arrighetti, in this situation, it's his bicep bias at delivery. We see examples of this phenomenon with pitchers like Sean Manaea and the success he's able to generate as a result as well.
Looking at his delivery, though, Arrighetti is able to achieve a deceptively low release height of 5.1’ from a 6.2’ frame. The reason he's able to achieve this is a combination of his outlier extension capabilities with a 7.2’ average last year, and the addition of his 25-degree arm angle. This ability opens up a number of possibilities with Arrighetti's arsenal, like the use of angles to produce flat VAAs on his fastball and easier capabilities to achieve breaking ball shapes. This low release height is one of the many reasons why I believe Arrighetti is prone to break out in 25’.
Retooling Location on 4-Seam
A main reason I believe Arrighetti will break out in 25’ is because of how good his 4-seam has the potential to be. I hinted at it earlier, but because of Arrighetti's low release height of 5.1’, he's able to produce an extremely low VAA of -4.2 on his 4-seam as a result. Despite this ability, Arrighetti only utilized the upper thirds of the zone with this pitch 43.1% of the time, which is well below the league average.
As a result, this pitch was rather ineffective, posting a .279 xAVG, .395 wOBA, .374 xwOBA, and a 19.8 Whiff%. What's interesting, though, is when Arrighetti played into his low VAA abilities, his 4-seam was much improved, producing a .202 xAVG, .331 wOBA, .306 xwOBA, and a 28.4 Whiff%. With these results and the understanding of how he could utilize his low VAA abilities in mind, I believe it's a no-brainer as to what Arrighetti should do in 25’. Priorities are placed on the upper third of the with his 4-seam!
Effectiveness of Breaking Pitches
To add to its great 4-seam capabilities, Arrighetti also has some of the best-performing breaking pitches in the league! In 24’, his curveball was able to produce a .124 xAVG, .227 wOBA, .180 xwOBA, 42.4 Whiff%, and a 31.1 O-Sw%, while his sweeper was just as good, producing a .176 xAVG, .186 wOBA, .226 xwOBA, 38.1 Whiff%, and a 32.5 O-Sw%. A primary reason for the effectiveness of these pitches is their great ability to play off each other because of their similar movement profiles. This ability allows him to achieve great swing-and-miss results.
To expand on what I was saying earlier, Arrighetti is a prime example of why you should view supination/pronation on a spectrum. Arrighetti, as I mentioned previously, is a pronator, but he has the capabilities to produce expansive breaking shapes, and they are great! If he was withheld from throwing these pitches because of strict guidelines for supination/pronation pitches, he most likely wouldn't have been as effective in 24’. We shouldn't limit pitchers to pitches just because they are on one side, but rather understand that some pitchers have the capabilities to have a mix of both!
Kick Change
Looking at Arrighetti mix, I think he could benefit mightily from adjustments to his current changeup. Due to Arrighetti being more of a bicep-dominant pitcher, he has limited ability to generate depth on his changeup effectively. As a result, this pitch just wasn't effective. In 2024, it only mustered up a .349 xAVG, .400 wOBA, .388 xwOBA, 37.8 Whiff%, and a 31.3 O-Sw%. Although it was effective at generating whiffs, it's evident that this pitch just can't limit damage when contact is made.
To help with this, I think Arrighetti should switch to a kick-change grip. This pitch would allow Arrighetti to produce more effective arm-side depth with a changeup while also allowing him to achieve greater velocity capabilities. An example of this pitch in action from a bicep-dominant supinator is Hayden Birdsong. In 2024, Birdsong revolutionized this pitch and was successful for the most part, producing a .238 xAVG, .297 wOBA, .278 xwOBA, 34.9 Whiff%, and a 28.4 O-Sw%. The addition of this pitch opens up movement possibilities that Arrighetti can't achieve with a traditional changeup grip, which is why I believe it's a very important addition to bolster his breakout campaign.
Conclusion
All in all, I believe that Arrighetti has what it takes to break out in 25’. He's shown the ability to be effective over stretches in 24’ by winning August Rookie of the Month, but he never put it all together. With some changes to a more consistent location at the top of the zone with his 4-seam, the continuation of his breaking balls, and a possible alteration of his changeup grip to a kick change, he could possibly be on the road to the next level of development. I know I believe he can, but do you?
Nice post.