Zander Mueth has one of the most unique fastballs in baseball

Shape characteristics gives Mueth an unique fastball

Photo Credit: WTM

It doesn’t take long for right-handed pitching prospect Zander Mueth to stand out on the mound. He throws from an extremely low arm slot, with a vertical release height of 4'7".

That gives him one of the most extreme releases of any pitcher that isn’t a sidearm/submarine-style pitcher.

It also gives him one of the most unique fastballs among the ones you can track on Baseball Savant since 2008.

When looking at pitch characteristics/shapes, a few things can help a fastball pop compared to others.

Induced Vertical Break (iVB), Vertical Approach Angle (VAA), Vertical Release Point (vRel), and Extension are among some measurable metrics that teams use now to get the most out of their pitchers.

Factoring all of those together, Mueth creates one of the more special fastballs in the minors and in recent history.

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Just looking at his sinker, a few things stand out. Standing at 6'7" helps Mueth get great extension on his pitches, with him getting seven feet of extension on the sinker.

I already mentioned the release height, he also has an incredibly flat approach angle for a ‘sinker’, meaning it’s probably more of a two-seamer than anything.

Finally, it averages about 14.7" of horizontal break on it, a pretty good mark.

Having any of those would be good; put them all together, and you have something you don’t see too often.

I looked at Baseball Savant’s Major League search tool to see how he compared to other pitchers when it came to iVB, HB, vRel, and Extension (Savant doesn’t have VAA data), and while lining up each category is easy, but finding others with similar metrics across the board was hard.

The slight red flag that pops up when looking at the list is that most with similar metrics are all relievers, mainly the vRel.

Kyle Crockett and Phillip Valdez are the two pitchers with similar fastballs to Mueth, not including VAA, which isn’t included on Baseball Savant.

Neither has pitched in the majors the last couple of seasons, Crockett last in 2018, and Valdez with the Red Sox in 2022. Crockett had a strong rookie season before fading out and was the Guardians’ (then the Indians’) 17th-ranked prospect going into the 2014 season on MLB Pipeline.

Two notable relievers that has fit close to his parameters, Phil Bickford and Seth Martinez.

Heading up on the vertical release point, Milwaukee Brewers prospect and former Top 100 prospect Robert Gasser has similar metrics. After undergoing Tommy John surgery, we will have to wait and see how they use him going forward.

Are there any starters?

With so many relievers as comps, does that mean Mueth is destined for a bullpen role? I dug a little further to try and find some starters in the majors during the 2024 season who had similar metrics on their fastballs.

There were a few, and one should be a familiar face. There may be a little sacrifice with one of the metrics, and some of their four-seamers come closer to Mueth’s ‘sinker.’

Joe Ryan is a data darling around the league, and you can see why. He doesn’t use the sinker often, and it has a steeper approach angle than Mueth’s, but outside of that, it’s a very similar pitch. Even the four-seamer has some similar characteristics, except it’s elite VAA and more iVB due to the pitch type.

The key with Ryan is the 4.3 BB%, which led to a 0.99 WHIP. Mueth threw his sinker in the strike zone 47% of the time, with Ryan throwing both his fastballs over 60% of the time for strikes.

Heaney might have the sinker most comparable to Mueth outside of the extension. The velo is close, the horizontal break is within a couple of inches, and the VAA is the same.

He’s a former top prospect who has established himself as a solid, back-of-the-rotation starter who doesn’t walk many batters. His arm angle varies from pitch to pitch and drops further for his sinker than any of the other pitches.

Since the ‘sinker’ is the only fastball Mueth throws, if you blend both characteristics from Ortiz, you can see the similarities. In fact, if you blend the two fastballs from Ortiz, they have the same pitch arsenals as each other.

Mueth is one of the more intriguing names in the Pirates system, and the arm angle is one of the main reasons. The control was bad once he got to Bradenton, so that will be something to monitor.

But the characteristics are there for Mueth to be one of the most unique pitchers in the majors should he make it there, and there are examples of similar players having success, just not many.