Baseball America picks an unusual suspect as Mariners' 2026 breakout prospect

Baseball America dug deep for their 2026 breakout prospect pick for the Seattle Mariners, and they didn’t land on the usual buzz-name from the organization’s upper tiers. Instead, they pointed to 2025 second-round pick Luke Stevenson.

On draft day, the book on Stevenson was pretty simple: elite defender, bat TBD. Even the most optimistic amateur scouts described the hit tool as “developing,” which is the polite way of saying “we’re crossing our fingers here.” And then Stevenson went out and made everyone look overly cautious. In 22 games with Single-A Modesto, he slashed .280/.460/.400, walking a ton, whiffing very little, and showing real pop when he got his arms extended.

Baseball America just circled Luke Stevenson as the Mariners catcher who could rocket into the Top 100

The numbers alone are encouraging — Power Four college bats should be able to handle Low-A pitching — but Stevenson’s underlying data tells the real story. A 15.1 percent zone-whiff rate is no joke for a freshly drafted catcher and his 104.9 mph 90th-percentile exit velocity hints at average-or-better raw pop. 

Combine that with Stevenson’s already-advanced defensive work, and Baseball America may have stumbled into the kind of breakout selection that ages extremely well.

But if Stevenson does break out in 2026, things get complicated in a hurry. Seattle is already navigating a catching logjam that most teams would kill for. Cal Raleigh isn’t going anywhere. Harry Ford is still one of the most intriguing, athletic catching prospects in baseball. And Stevenson? Well… there are only so many innings to go around.

That’s where the questions start bubbling up. Does Stevenson become a trade chip if he forces the issue? He might already be trending that way. He appeared in our recent ranking of four prospects the Mariners could consider shopping this offseason. Catching is one of the sport’s most valuable currencies, and a defensively gifted backstop who can actually hit is basically baseball’s version of Bitcoin.

There’s also a scenario where Stevenson accelerates through the system so quickly that the Mariners have no choice but to rethink the organizational puzzle. If he’s legit, someone eventually has to move, and the most logical candidate is Ford — whether that means shifting him to the outfield, or turning him into the kind of ultra-versatile cornerstone player Seattle seems determined to develop.

This pick isn’t flashy, but it’s fascinating. A breakout from a catcher the Mariners didn’t need could end up forcing a long-term decision they can’t avoid.