Jerry Dipoto drops a hilarious Cal Raleigh comp on RHP prospect Ryan Sloan

There are prospect updates, and then there are prospect updates that make you spit out your coffee. Per The Seattle Times, Mariners POBO Jerry Dipoto looked at Ryan Sloan and admitted the unthinkable: he “might have a larger lower half than ‘The Big Dumper’” Cal Raleigh.

That’s where we are with Sloan. The 20-year-old right-hander walked into big league camp like he was created in a lab. He immediately gave the organization the rarest gift in baseball: a reason to laugh and dream at the same time.

The funniest part is the joke lands because Sloan’s stuff is already doing the serious talking.

Mariners’ Ryan Sloan is already forcing an uncomfortable fast-track conversation

Start with the visual: Ryan Divish posted the live BP footage that begins with Sloan uncorking a 99 mph first pitch to Raleigh, which is a pretty aggressive way to introduce yourself to the face of the franchise’s catching room.

And per MLB.com’s spring training notes, Sloan didn’t just show max effort heat — he showed impressive command that makes player-development people start using words like “not-too-distant.” Jerry Dipoto even said you wouldn’t know Sloan hasn’t pitched above A-ball by watching how he repeats his delivery and commands the baseball. 

The “bigger-than-Big-Dumper” comp is hilarious, but it’s also kind of a tell. This front office isn’t giggling because they saw a strong kid in the weight room. They’re grinning because a 6-foot-5 power arm is doing the hard part early — throwing strikes with premium stuff.

MLB.com notes that Sloan threw first-pitch strikes to 73 percent of hitters last year, and that strike-throwing foundation is exactly why Seattle feels comfortable “installing” new weapons instead of just letting him rip fastball/slider forever. The Mariners are delicately bringing along a two-seamer and want him to use his changeup more in 2026 after it was only 8 percent of his mix last year, with the goal being the obvious one: turn a monster athlete with a big arm into a starter with a real four-pitch menu. 

The slider? That’s where it gets unfair. In the same live BP, Sloan finished Randy Arozarena with a slider that had 20 inches of vertical break, per Mariners pitching strategist Trent Blank. Twenty inches is cartoonish movement even in a sport that’s basically become a movement arms race.

Which brings us back to a line from Keith Law of The Athletic that keeps sticking in your brain: if there’s any concern, it’s that Sloan is so good, so soon. That’s a good kind of dilemma — not whether he’s ready, but how aggressive you want to be with the assignment.

All signs point to Sloan opening at High-A, potentially sharing a rotation with Kade Anderson, which is honestly a pretty good excuse to take a trip to Everett. If Sloan is already touching 99, landing a bat-missing slider, and learning the “Mariners starter toolkit” (two-seam shape + real changeup usage), the Big Dumper comp is just the appetizer.

The main course is the possibility that Seattle might have another homegrown freak on the way — one with legs like a mythological creature and a fastball that makes even Cal Raleigh do a double take.