Seattle Mariners select LHP Mason Peters in fourth round of 2025 MLB Draft
The Mariners go back to the college pitching ranks in the fourth round of the MLB Draft for a bullpen arm
After an exciting Day One of the MLB Draft where the Mariners held several high picks, the draft resets to the traditional reverse order of standings for rounds four through twenty, meaning the Mariners pick towards the end of the round. With their fourth-round selection, the Mariners went back to the college ranks, and back to college left-handed pitching, specifically, taking LHP Mason Peters out of Dallas Baptist.
Peters began his career at Temple Junior College before transferring to DBU, a pitching-focused program the Mariners have drafted out of before in recent years (Cal Hernandez in 2018, Jarod Bayless in 2019). Peters primarily worked out of the bullpen at DBU, posting a team-high four saves, but he also has the ability to go multiple innings and DBU was able to lean on him at times as a starter, as well. He was the starting pitcher (6 IP, 10 K) as part of a combined no-hitter at DBU this season, the fourth in school history.
Peters is an undersized (5’11”) left-hander with a fastball that sits at 93 and touches 96, but he’s been able to miss bats thanks to his best pitch, a high-spin slurve that has a ton of depth and some break, as well as above-average spin (3000 rpm). Here’s the pitch in action:
Dallas Baptist closer Mason Peters was a buzzy name entering the season after impressing throughout the fall and preseason with a potent two-pitch mix. He regularly achieves 3,000 RPM on a big breaking ball (seen below). Name to follow. pic.twitter.com/ffIS2XoHrx
— Jacob Rudner (@JacobRudner) March 12, 2025
It’s mostly a two-pitch mix at present, but there’s enough here to think they might view him as a long relief/back end starter project. He’s most likely a bullpen piece long term; however at just 21 years old, perhaps the Mariners see him as a piece they can unlock something in and turn him into a sneaky good pick up.
TEN strikeouts through six innings for Mason Peters... #BestBaseballinDallas pic.twitter.com/JXWzIlfsSv
— DBU Baseball (@DBU_Baseball) May 17, 2025
It seems as though this pick will afford them some cash as he wasn’t on most major outlet’s top three hundred prospects list, however it seems unlikely the money saving trend will need to continue in order to afford second rounder Nick Becker. This deal should afford the Mariners a few hundred thousand in savings, and when added with the chunk of change they saved with Anderson and Hugus, they’re likely very close to even or back in the black.