Ryan Sloan only needed 12 pitches to ignite Mariners fans in spring debut

Look, let's not oversell Ryan Sloan's Cactus League debut for the Seattle Mariners on Sunday. In the pantheon of talented prospects entering the spotlight, this wasn't exactly Stephen Strasburg in the capital back in 2010.

Even so, when the storyline is "fast-rising 20-year-old makes his first spring appearance," you move to the edge of your seat. And when that guy then pitches a perfect inning, you jump out of it.

The only real shame of Sloan's appearance against the Texas Rangers on Sunday is that it only lasted 12 pitches. It was a frustratingly small taste of his talent, even if it was still enough for him to dial up a pair of 99 mph fastballs, one of which caught Josh Smith looking at strike three.

Granted, we'd be having a slightly different conversation if Smith had tapped his helmet in time to apply an ABS challenge. But he didn't, hence why this appreciation post for MLB Pipeline's No. 33 prospect is a full go.

Ryan Sloan showed why he's a future Mariners ace in his spring training debut

There is only so much to be gleaned from the metrics on Sloan's 12 pitches from Sunday, but what's there is encouraging. He averaged 98.2 mph on the fastball, and its peak of 98.9 mph is the fastest that any Mariners starter* has reached this year.

*Sloan technically appeared in relief of Logan Gilbert, but he's not a reliever in the same way that Andrés Muñoz and Carlos Vargas are.

Sloan's four-seamer also had 15 inches of induced vertical break and four inches of horizontal break. Between that movement profile and its velocity, there's a bit of similarity between Sloan's four-seamer and that of Cam Schlittler, whose heater became one of the modern wonders of the baseball world in 2025.

The other pitch Sloan flashed as much as his four-seamer on Sunday was his sweeper, which averaged 84.5 mph with 16 inches of horizontal break and -2 inches of induced vertical break. Think "Dustin May's sweeper," and you're there.

The caveat of throwing major league comps on a guy like Sloan is that it's kind of unfair. He is his own pitcher, not one assembled from parts of other pitchers. And as talented as he is, he's still a long way from the majors. Last year was his first pro season, and he only made it as far as High-A.

All the same, the Mariners aren't hiding how high they are on Sloan. Beyond just how talented he is, his poise caught Dan Wilson's attention on Sunday. As he said afterward, via Jesse Borek of MLB.com: “Even talking to him on the bench afterwards, nothing really seems to shake him, and that's something that you really like to see."

MLB Pipeline has Sloan's major league ETA at 2028, and it'll take more than one spring training outing to bump that number down to 2027 or 2026. But if nothing else, it's harder than ever to foresee that number somehow going up.