Mariners farm system might possess the 2 best LHPs from the 2025 MLB Draft

There's a saying that sometimes it's better to be lucky than good. The Mariners proved this twice in the 2025 Major League draft, by first jumping up 12 spots to the third overall pick in the lottery and then selecting Kade Anderson after the Nationals and Angels passed on him. And now we might have to make it a three times lucky with the 2025 draft, thanks to fellow lefty Mason Peters.

Anderson has been as advertized (if not better), but to say Peters has been a revelation for the Mariners in Single-A Inland Empire would be an understatement. Through the first eight starts of his minor league career, he's produced a 1.74 ERA and 0.903 WHIP. For some more context of just how effective he's been, he has 45 Ks and just seven free passes during his 31.0 combined innings of action.

There's no real need to go out of the way to make Peters' form seem even more impressive. But we'll do it anyway, in noting that half of the six total earned runs he's allowed so far in 2026 came in his first start of the season. Irrespective he's receiving plenty of attention, including some love from Seattle Sports, complimenting his three-pitch repertoire which includes a fastball, curveball and slider.

Peters' best weapon is arguably his curveball, although his scouting report notes his overall pitching is helped by an athletic, repeatable delivery that's made him the No. 15 prospect in the Mariners farm system. As such, maybe it's not that surprising he's throwing lots of strikes and getting plenty of whiffs.

Mason Peters overshadowing 2025 first round lefties not named Kade Anderson

It truly is impressive to see Peters performing so well, when you consider he wasn't selected until the fourth round of the 2025 draft, with 13 southpaws picked between Anderson and him. And the reality is there hasn't been a lot of success so far outside of the Mariners duo, highlighted by the three lefties taken after Anderson:

It's important to note Peters didn't have much of a college career, so this is a clear case of the Mariners pitching lab seeing stuff that they could work with. Interestingly, he was mostly deployed as a reliever during his limited college career (16 out of 20 appearances in NCAA), but clearly the M's organization has seen enough to develop him into a full-time starter.

The next steps will include increasing Peters' workload (currently pitching 4.0 innings per outing) and eventually seeing how he performs higher up the minor league ladder. For now though, while we appreciate it's still early days, it's tough not to be impressed by what the 22-year-old has achieved.

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