Kansas City’s Alec Marsh Weighs In on His Weird Fastball

Red Sox hitters will be facing an enigmatic fastball when they host the Royals at Fenway Park tonight. When Eric Longenhagen put together our Kansas City Royals Top Prospect list last month, he wrote that Alec Marsh’s fastball “doesn’t hop even though it has the approach angle and spin axis of a fastball that typically does; it has below-average vertical break and might be surprisingly hittable against big league bats.” Calling the pitch “weird,” our lead prospect analyst further described it as a “flat-angled, high-spin sinker,” adding that the 25-year-old right-hander, whom he assigned a 45 FV and a no. 3 ranking in the system, is no longer touching triple digits as he did in his initial seasons of pro ball.

Intrigued, I showed the 2019 second-round pick out of Arizona State University what my colleague had written, and asked him a simple question: How accurate is this?

Here is Marsh’s response to that, as well as a smattering of other questions.

Alec Marsh: “I’d say 100%. Two years ago, when I was throwing that hard… I mean, I ran into velo for about a year before I got hurt [a biceps injury in 2021], but I never really touched 100 [mph]; I touched 99 maybe once a start. My vertical and horizontal were pretty elite back then. I would touch 20s and be around 8–10 horizontal. When I came back from injury, I started really cutting the ball. I don’t know if it was because of a trust factor of pronation and stuff like that, but when I was in Double A last year, I gave up a ton of hits and home runs on fastballs, just because I was in that super hittable zone of 93–94.

“The vert being down… I mean, it would go down to 12 sometimes. I think I was chasing the vert numbers so much that it almost made it worse. That kind of haunted me all season, because it was the only thing I was looking for. I didn’t want to work on other pitches or fix anything else; I was just focused on trying to fix the fastball.

“I finally let it go and came to terms with ‘It is what it is, and you’ve got to be able to use your other pitches, because the fastball is more hittable right now.’ That doesn’t mean it won’t get better. It was more about not putting so much stock into, ‘You have to get this better or you can’t pitch.’ Basically, I changed my mindset to, ‘You have four good pitches and can utilize them to get deep into games; you can use the fastball more effectively by making the command better.”

“So I think [Longenhagen’s] was a great take. Before I got injured, the fastball was more hoppy. I got more swing-and-miss, I got more foul balls, even when I left it over the middle of the plate. Now when I leave my fastball over the middle, it usually gets hit.

“Coming back from injury and not being able to pronate as much… I mean, I can’t get to the back of the ball, so I’ve kind of been releasing it on the side. A lot of my pitches are almost that cutter-look fastball, but it’s more of like an up-shoot vert ball. It was actually really good against the Rays [on July 15], though. I dominated them [11 strikeouts and five hits allowed in six innings] with fastballs. I didn’t get much swing-and-miss on other pitches, but the fastball was good.”

Laurila: So it has been good at times this season?

Marsh: “I am starting to figure some things out with the four-seam. I just threw a bullpen and had a lot of 20-inch fastballs out there. The numbers in the ‘pen are a lot better than they are in games right now. I assume that’s just because of adrenaline cutting it off a little bit in games. I know it’s going to translate eventually. It’s a matter of getting there consistently and doing it in games.

“Hopefully the velo will start to come up a little bit, too. My average velocity this year [94.7 mph in 28 big league innings] is maybe a tick better compared to last year, but the end range isn’t as high. I’m not touching 99. But do I think it will be there some day? For sure.”

Laurila: And it is a four-seam, and not a two-seam?

Marsh: “Again, what he wrote is accurate, although it’s not a sinker. I think it’s like a vertical approach angle… it’s like an up-shoot fastball with weird metrics: high spin rate [2,486 rpms] but low vert. My horizontal is back to normal. Last year it was five, because I was cutting it a lot, and this year it’s back up to seven or eight.

“So yeah, I’m not throwing a two-seam or a sinker. At least not yet. I had a sinker when I got drafted, so I might add it back in the future and be a five-pitch-mix guy. For now, I just need to work with what I have.”