The Mariners have recreated a tremendous pitching success story with latest starter

When the Seattle Mariners acquired right-hander Casey Legumina from the Cincinnati Reds back in February for cash considerations, the move barely registered. It looked like another low-risk dart thrown at the bullpen wall during an offseason filled with similar moves to bolster depth at the position.

But just two months into the 2025 season, that transaction is beginning to look like yet another masterclass by Seattle’s pitching development system — a quiet coup with echoes of Paul Sewald’s breakout.

Legumina came to the Mariners with little fanfare and even fewer major league results. Across parts of 2023 and 2024 with the Reds, he struggled to a 6.95 ERA over 17 appearances. His arsenal didn’t light up radar guns and quite frankly it still doesn’t. There was no hype train rolling in behind him. But the Mariners saw something worth betting on — a mix of control, pitch shape, and a savvy approach that might translate into something more with the right coaching and environment.

How the Mariners are repeating their Paul Sewald success with a new arm

This should sound familiar. The Mariners turned a similar formula into gold with Sewald, who reinvented himself in Seattle after middling seasons with the Mets. Like Sewald, Legumina doesn’t overpower hitters with velocity, but he thrives on execution. And through the early going in 2025, the results are undeniable.

In 15 appearances for Seattle, Legumina has delivered scoreless outings in 14 of them. He’s quickly become a go-to option when the Mariners need stability on the mound — especially as the bullpen continues to shape its identity. Even more telling, he’s starting to earn high-leverage opportunities, including working the eighth inning in each of his last two outings.

That level of trust speaks volumes about his consistent execution and poise. He’s even been tapped for a spot start as an opener in the Mariners' current series against the White Sox — a clear sign the coaching staff is ready to lean on him in a variety of roles.

The numbers don’t lie. Legumina’s expected batting average (xBA) ranks in the 97th percentile, which is especially impressive considering his 94.1 mph fastball doesn’t reach elite velocity tiers. What he lacks in heat, he makes up for with precision and movement. Hitters simply aren’t squaring him up, and the data backs that up with every outing.

There’s a reason Mariners personnel are raving about him internally. He’s embraced the team’s philosophy of attacking hitters early and maximizing the effectiveness of his pitch mix. The transformation has been swift and meaningful — “Legs,” as he’s affectionately called in the clubhouse, is becoming a trusted arm in a bullpen that really needed one to step up.

And while it’s still early, the trajectory is promising. The Mariners may have once again unearthed a gem from another team’s discard pile, proving once more that when it comes to rebuilding bullpen arms, no team is more resourceful than Seattle. If Legumina continues trending this way, don’t be surprised if his name is in the middle of some big moments later this summer.