Mariners' latest unhittable pitching prospect has to be seen to be believed

By now, Seattle Mariners fans should know that the High-A Everett AquaSox have an absolutely loaded roster. But since arguably their best pitcher exists in relative obscurity, consider now a good time to get to know Tyler Cleveland.

At 25, the right-hander is a little old to still be pitching at High-A. He was also a mere 14th-round draft pick in 2022, and he doesn't appear among the Mariners' top prospects for MLB Pipeline orBaseball America. With his 26th birthday due up on September 9, whether he should even be called a "prospect" at this point is debatable.

And yet, he's busy proving that one need not have an impressive pedigree to mow down hitters. Indeed, sometimes all it takes is a funky delivery that has to be seen to be believed.

Nobody can hit Tyler Cleveland, and it makes sense once you see him in action

Through 14 appearances for Everett, Cleveland has pitched 21.1 innings and yielded only three earned runs on eight hits (all singles, no less) and seven walks. He has struck out 21 of the 82 batters he has faced.

If this doesn't intrigue you, the sheer visual splendor of Cleveland's pitching delivery will:

There are sidearmers, and then there sidearmers. Cleveland is the latter, and the Mariners have his time with the University of Central Arkansas baseball team to thank for that.

Here's how Cleveland explained the origins of his sidearm delivery in 2022:

" [My] over the top was pretty average, and to be a difference maker in our program, I wasn't where I needed to be, the consistency wasn't there. And that's what we preach [at UCA]. I knew from the series at Southern Miss during the COVID-19 year, that I was going to have to change because I just couldn't figure it out. And I embraced it, and then COVID happened and I was able to practice it all the time playing summer ball. And it just naturally happened, being an athlete and being free and letting it go."

Tyler Cleveland

Writing about Cleveland in 2023, Eric Longenhagen of FanGraphs praised the righty as being "extremely athletic" and as having "fantastic command" of a mid-80s fastball and a mid-70s slider. Cleveland was a starter at the time, and Longenhagen posited that his velo could tick up in relief.

Whether his velo has indeed improved since he moved into relief work in 2024 is not clear, but Cleveland has definitely cleaned up his walks. His rate of free passes per nine innings is down from 5.3 in 2024 to 3.0 in 2025

As for the hits, well, they're just not there. He has unsurprisingly been especially deadly against right-handed batters, holding them to two hits in 34 at-bats with 13 strikeouts against three walks.

This is one reason for the Mariners to think that Cleveland could at least be a specialist in the big leagues. The other is that his delivery would be a rarity, if not a one-of-a-kind. The widest release point for a righty currently belongs to Matt Bowman of the Baltimore Orioles, and Cleveland has three inches of additional height on him.

At the very least, Cleveland has established himself as an underdog worth rooting for. And given that he's standing out even next to name-brand prospects like Colt Emerson, Lazaro Montes, Michael Arroyo, and Jurrangelo Cijntje, he ought to at least be on the big club's radar.