Seattle Mariners See Valuable Coach Leave Organization

The Seattle Mariners suffered a disappointing coaching loss this week, as it was reported on Tuesday that Triple-A hitting coach Shawn O’Malley has left the organization. He is now on the major league staff as an assistant hitting coach for the Washington Nationals. It’s certainly a promotion for him, but it’s a loss for the M’s, undoubtedly.

We caught up with O’Malley on an August edition of the ‘Refuse to Lose‘ podcast, which shed some light on what made him such a valuable member of the M’s family.

A Washington native, the 37-year-old O’Malley was a fifth-round pick of the Tampa Bay Rays in 2006 MLB Draft. He made his major league debut for the Los Angeles Angels in 2014 and then spent parts of two seasons with the Mariners.

An excellent utility player, he hit .231 for his career with three home runs and 11 stolen bases. He played a career-best 89 games for the M’s in 2016, moving all over the field.

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O’Malley oversaw some of the M’s most important players and prospects in 2026 while working with the Rainiers. He’s partially responsible for the positive changes with Dominic Canzone and was part of the development for Cole Young and Harry Ford. When Ben Williamson was sent down following the acquisition of Eugenio Suarez in late July, O’Malley helped him unlock some more power.

In that August conversation, he had this to say about his work with Canzone, who was recalled by the Mariners on June 9 and hit .300 with 11 home runs and a 142 OPS+.

The way I work too, is like, I’m not just going to tell you what to do. Like, this is a ’we’ thing. So a lot of it was looking at his old swing, finding out, like, ’hey, what do you want to do?’ This is your career. How can I help you moving forward?’ So a lot of it was just walking back to things that he’s learned in the last few years, but also going back to what got him there in the first place. So, that was a lot of it. And a lot of it was just me helping steer while Dom figured out what he needed to do and how he wanted to do it. And I was just just there to help guide him.

I caught up with Canzone in September during a series against the Houston Astros and asked him about some of those conversations with O’Malley and figuring out what kind of hitter he wanted to be:

I think in the past, like, kind of when I got called up here and stuff like that — the damage was mostly — they just wanted me to hit a lot of doubles and homers was just kind of the vibe that I got,and with this new staff, the objective was just to hit line drives up the middle and and the other stuff will come with that. So I think just more just simpleing down the approach and it’s really allowed myself to be a complete hitter, and I think it’s helped a lot of other guys do the same.

In addition to O’Malley, the Mariners have seen bullpen coach Tony Arnerich depart for Cleveland, as well as Andy McKay. They also lost third base coach Kris Negron, who went to Pittsburgh.

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Seattle Mariners See Valuable Coach Leave Organization

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