Ron Marinaccio throws a unicorn changeup

I bet that you didn’t know who Ron Marinaccio was going into the 2022 MLB season. That’s because you don’t typically find career-long minor league relievers that high up on prospect lists. In fact, unless you’re following a team’s organization from top to bottom, this is the type of player who you sometimes don’t hear about until you find them high up a leaderboard when you’re scrolling through a site like FanGraphs.

Well, you should get to know Ron Marinaccio. Our own Chris Guay covered the right-hander last week and Dan Kelly detailed his development track. He has been very effective in his first season in the big leagues with a 2.60 era in 17.1 innings. That’s a nice debut for a 26-year-old rookie who has been marinating in the minors since 2017 after being drafted in the 19th round out of the University of Delaware. The reason I want to talk about this Yankees rookie is to marvel on his unicorn changeup. Let’s start how we always do with some video:

That’s two whiffs against extremely talented hitters in Jose Altuve and Adley Rutschman, one from each side of the plate.

Marinaccio’s changeup is the sort of frisbee that you take notice of as soon as you see it. It’s almost surprising to see it come from the windup too. His slight hitch and above-average extension give him added deception, which plays up his pitches. However, it also helps in creating some wicked horizontal movement. The pitch induces 17 inches of horizontal break, which stands near the top of the league and is comparable to his fellow reliever, All-Star candidate Michael King, from an extension and movement standpoint.

But the movement isn’t what makes Marinaccio the unicorn. He is very close to the top of that leaderboard, but not quite atop near the Devin Williams and Garret Whitlocks of the world. What makes him special is a stat that I’ve discussed a few times this year when referring to some Yankees pitchers, horizontal approach angle (HAA). Of all the pitchers who have Marinaccio’s level of horizontal run on their changeup and up, none come close to his -1.5 degree HAA.

For a quick recap, HAA indicates the horizontal sharpness that a pitch has when it enters the strike zone. Marinaccio’s -1.5 degree entry means that his changeup enters on a sharper horizontal angle towards a right-handed batter than any other changeup with that level of horizontal run. In fact, the next closest are the aforementioned King himself and Twins starter, Joe Ryan, with a -0.8 degree HAA. That is almost double the next guy! Combine that with his low release point and great extension relative to comparable pitches and you have yourself a unicorn. The numbers against the pitch are backed up too. Hitters have been awful against it, with only a .042 batting average and .083 slugging percentage.

I love unicorn pitches. It’s not often on a baseball field that you can say, “I do this differently from anybody in the world.” Marinaccio can though, and it’s a big reason for his success in the minor leagues and in his time in the bigs this year.

When you have an outlier trait of any kind, the odds that you can stick around the big leagues for a long time are pretty high. That’s the goal nowadays in pitching development: Find the outlier trait if it’s there, and then adapt the rest of the repertoire in whatever way necessary to maximize that outlier trait. We’re seeing it happen in real time with Marinaccio. Get used to seeing this other kid from Toms River, NJ.