Projecting the Mariners Opening Day roster
The Mariners report to Spring Training this week, so let's project their roster
The Super Bowl is over, and the Mariners report to the Peoria Sports Complex this week to get 2025 Spring Training underway.
In the four months since the World Series, the Mariners did remarkably little to change the look of their roster. They have the exact same starting rotation, basically the same offensive group, and didn’t sign a reliever to an MLB contract. In total, the Mariners’ 40-man roster has just SEVEN new players on it from outside the organization, and an eighth who was added to the roster from the minor leagues. For context, Jerry Dipoto turned over the ENTIRE 40-man roster in his first four years running the organization.
Still, despite a roster filled with incumbents, the Mariners have a lot of playing time up for grabs. For one, a lot of the incumbents don’t exactly scream irreplaceable, and also, the outside solutions don’t carry proven track records. Even with more than 30 familiar faces, there’s as much opportunity available in the Mariners lineup and bullpen than there’s been since at least 2022, and a greater volume of intriguing players in the mix than usual as well.
Starting Pitching
Logan Gilbert, RHP, 27 years old
George Kirby, RHP, 27
Luis Castillo, RHP, 32
Bryce Miller, RHP, 26
Bryan Woo, RHP, 25
Depth: Emerson Hancock (RHP, 25), Logan Evans (RHP, 23), Blas Castano (RHP, 26)
The Mariners rotation didn’t change a bit since the end of 2024, and that’s a good thing. Even though this group couldn’t ultimately overcome the terrible offense the Mariners played in 2024, the front office correctly recognizes that their group of nasty right handers form the core of their squad. In a testament to self-restraint, Dipoto combated his trade addiction successfully and avoided swapping out any of his golden arms, despite other teams calling on them almost exclusively this offseason. Faced with a clear path to making huge trades before the 2025 season, Dipoto defied his reputation and didn’t tinker.
The “who is the Mariners ace?” discourse is largely meaningless and unproductive, but after 2024, it’s quite clearly Gilbert in my eyes. In his first three full MLB seasons, Gilbert has pitched the most innings in the American League and the fourth-most in all of baseball. He led MLB with a preposterous 0.89 WHIP in 2024, made his first all-star game and received his first AL Cy Young votes, finishing sixth. Perhaps the most telling indicator that he’s ascended to Mariners acedom? That’s his 9-12 record in 2024, with the run support in keeping with the hallowed tradition of King Félix.
Behind Gilbert, Kirby offers the most ace-like package, but his 2024 showed signs of a speed bump for his strike-heavy style. While he delivered another MLB-leading K/BB season and still racked up 4.2 fWAR, he led the American League in hits allowed, showing the first signs of cracks in his superstar ascent. Like Kirby, the duo of Miller and Woo both look likely to take steps forward in 2025. Miller’s incredible work ethic and knowledge of the game could take him to the very top of the sport if the former fourth-round pick keeps defying the odds. Woo shrugged off an injury-riddled first half of 2024 to massively breakout in the second half, and he seems likely to continue rising rapidly as long as he holds up physically.
Castillo stands in contrast to the rest of this group in 2025 as a pitcher possibly in decline. After 1.5 seasons of borderline ace-level contribution for the Mariners, Castillo was much closer to average in 2024. With that in mind, the Mariners front office seemingly spent a significant chunk of this offseason trying to trade La Piedra and his remaining three years and roughly $70 million, to no avail. Seattle could definitely use some top-tier stretches from its highest paid player in 2025.
The Mariners’ depth beyond their top group gets dicey quick, although that’s largely a function of the roster-building model they’ve employed. With a tight budget and established rotation, they’re not going to be able to afford big guarantees to sixth starters, and they’ll need to rely on minor league veteran fliers and their player development for depth in case of injury. Their 2020 first-round pick Hancock is the clear sixth man, and he played that role to the tune of 12 of the most meh starts you’ll ever see in 2024. Hancock’s pro career has had a ton of ups and downs to this point, and 2025 could be a make-or-break year for him. After Hancock, Evans offers the most compelling blend of upside and MLB readiness. The Mariners abandoned a brief attempt to make Evans a super reliever in 2024, and after 107 AA innings, he’s got a shot to debut in Seattle’s rotation at some point this year. Castano was picked up from the Yankees in 2023 and performed well enough in 32 starts at Arkansas and Tacoma the past two seasons that the Mariners made a point to add him to their 40-man roster. He and the recently DFA’d Jhonathan Diaz are in the mix behind Evans.
There will likely be a few more names to emerge for spot start opportunities in 2025, as pitcher health is never guaranteed. That said, entering Spring Training, this is probably the most formidable rotation the Seattle Mariners have ever had.
Offense
Julio Rodriguez, CF (R), 24
Cal Raleigh, C (S), 28
Randy Arozarena, LF (R), 29
J.P. Crawford, SS (L), 30
Victor Robles, OF (R), 27
Luke Raley, 1B/OF (L), 30
Jorge Polanco, 3B? (S), 31
Donovan Solano, 1B/3B/DH (R), 37
Dylan Moore, 2B/3B/SS/OF (R), 32
Mitch Garver, C/DH (R), 34
Mitch Haniger, DH/OF (R), 34
Leo Rivas, 2B/SS (S), 27
Austin Shenton, DH/1B/3B (L), 27
Depth: Ryan Bliss (2B, R, 25), Cole Young (2B/SS, L, 21), Tyler Locklear (1B, R, 24), Dominic Canzone (OF, L, 27), Blake Hunt (C, R, 26), Miles Mastrobuoni (UT, L, 29), Nick Dunn (2B/3B, L, 28), Ben Williamson (3B, R, 24)
Of the 13 names projected above, 11 ended the season on the roster. Polanco, the team’s big offseason splash for two years running, will switch to 3B, and the Mariners will paper over the departure of Josh Rojas and Justin Turner with Solano and Shenton. If that sounds underwhelming to you, I don’t blame you.
The Mariners’ offensive quality comes from their outfield and up-the-middle core. Rodriguez, Arozarena, and either Robles or Raley forms one of the best starting outfields the Mariners have had in a long time. Raleigh is the best all-around catcher in baseball, and Crawford, coming off a down year at the plate marred by injuries, feels like a lock for 2-3 WAR season if his defensive rebound holds.
The infield picture is much messier. Raley, a shockingly athletic corner OF, looked poor defensively at 1B in 2024, and is unlikely to play against left-handed starters. Solano, who’s seemingly too old to contribute at difficult defensive positions, will platoon with Raley and see significant DH starts. Polanco has just 24 career MLB appearances at 3B and 15 since he was 22, all during the 2023 season. Moore, who played more than 30 games at all of 2B, 3B and SS in 2024, projects to start at 2B for time being. Mariners GM Justin Hollander name checked Rivas last week on Seattle Sports 710, and he’s likely to backup all three of those positions as well. Shenton’s lack of defensive acumen makes him more of pure bat, but he could potentially factor in at the corners. For a team that claims to have significant playoff aspirations, it’s a distressingly uncertain infield situation.
The situation would drastically improve if the Mariners saw a breakout from Bliss, Young or Locklear. Bliss and Locklear both had small-sample debuts in 2024 and showed promise along with significant flaws. I kept Bliss off the Opening Day roster based on Hollander indicating Moore would start at 2B. While Bliss has the athleticism and sneaky pop to make an impact, his defensive limitations make him a less versatile bench contributor than Rivas. Bliss could see his opportunity arise the same way it did in 2024, were Polanco to (inevitably) get injured and Moore’s services be required at the hot corner. Locklear had a so-so MLB debut and a so-so 2024 in AAA Tacoma, which is presumably why the Mariners pushed hard this offseason to sign a RHH 1B instead of handing that job to the former Top 100 prospect. His best path to MLB reps may be through an injury or release involving Haniger, which would free up some regular DH opportunities.
Young deserves his own paragraph here, as he’s the first Top 100 prospect on offense with a real chance to debut on the Opening Day roster that the Mariners have had since Rodriguez in 2022. The Mariners 2022 first-round pick, called an “OBP prodigy” by Fangraphs, had solid 2024 season in AA. The starting 2B role seems to be calling his name, and a big Spring for the left-handed hitting Young could make it hard for the Mariners to shrug their shoulders and run Moore out against a ton of right-handed pitchers. An MLB debut after a few months in Tacoma seems more likely for Young, but it won’t take much for the Mariners to turn over their barren keystone.
The Mariners still have a less-than-dynamic duo of Mitches weighing down their bench. Naturally, due to the harmonious blend of Dipoto’s roster construction and ownership’s budget restrictions, the third- and fourth-highest paid players on the Mariners combined for -1.0 fWAR in 2024. The pair of them return in 2025, Garver as the likely backup catcher who will feature as a DH against LHP, and Haniger as some sort of veteran right-handed bench bat. Seattle would surely jettison both in a second if they could, but for now will hope reduced roles will lead to pressure-free production for wily veterans with nothing to lose.
The final bench spot is totally up for grabs, owing to the fact that, as mentioned, the Mariners did very little to improve this offseason. Count me down for Shenton, both as a former Mariners farmhand come full circle and as a nice opportunity for the Bellingham High School graduate. Shenton’s bat seems more stable and ripe for a bench role than the mercurial Canzone, who posted an unfathomable -79 wRC+ in 22 high-leverage plate appearances in 2024. Another potential option for the final spot is Dunn, a longtime Cardinals farmhand who is not Ben Affleck, although he does share the name of his character from Gone Girl. The Mariners signed Dunn to an MiLB pact before the end of the World Series and his track record in the high minors makes it obvious why. He has nearly as many career walks as strikeouts and has hit comfortably over .300 from the left side over the past two seasons in AA and AAA. Were a lot to go wrong with plan A at either 2B or 3B, Dunn could offer useful depth, despite never having debuted in MLB.
Personally, I don’t think Mastrobuoni and Hunt, the two sparest parts of the hitters on the Mariners’ 40-man roster, have a chance to make the team without a significant injury. Ditto for Williamson, although he merits mention because he plays the Mariners biggest position of need, 3B, at an insanely high level. Despite a middling offensive profile, Williamson is regarded as one of the best infield defenders in Minor League Baseball, as well as easily the Mariners’ strongest defensive third baseman.
Bullpen
Andrés Muñoz, RHP, 26
Gregory Santos, RHP, 25
Collin Snider, RHP, 29
Trent Thornton, RHP, 31
Eduard Bazardo, RHP, 29
Gabe Speier, LHP, 29
Tayler Saucedo, LHP, 31
Will Klein, RHP, 25
Depth: Cody Bolton (RHP, 26), Hagen Danner (RHP, 26), Casey Legumina (RHP, 27), Carlos Vargas (RHP, 25), Brandyn Garcia (LHP, 24), Drew Pomeranz (LHP, 36), Neftalí Feliz (RHP, 36), Shintaro Fujinami (RHP, 30), Jesse Hahn (RHP, 35), Adonis Medina (RHP, 28)
Injured: Matt Brash (RHP, 26), Jackson Kowar (RHP, 28), Troy Taylor (RHP, 23)
The Mariners took a group that badly lacked a dependable late-inning nucleus in 2024 and didn’t add a dependable late-inning reliever to that mix for 2025. This approach to bullpen building is another result of the marriage of Dipoto and Mariners ownership, although they’ve mostly thrived in creating effective bullpens this way prior to 2024, when the strategy showed significant diminishing returns.
The most important name in the mix is Muñoz, but less needs to be said about him than any other. He had a great 2024 and posted 22 saves as a full-time closer, although his K% continued to drop and he struggled away from home. The Mariners desperately need an 8th-inning option to emerge alongside him, and they probably would love it to be Santos, whom they acquired in 2024 from the White Sox for a pair of fringy prospects and a top-70 pick in the most recent draft. Santos battled a whole host of different injuries last season and only appeared in eight games. He has an electric arm, but might not have the durability to sustain a late-inning workload. The arm who did emerge alongside Muñoz in 2024 was Snider, a sneaky February 2024 waiver claim whom the Mariners told to throw his sweeper more and throw more strikes, which led to a nice little sun run as the 8th-inning guy last summer. Snider seems most likely to get the first crack at the 8th inning in 2025.
That’s because the Mariners’ true 8th-inning guy, Matt Brash, has been missing in action since the end of the 2023 season, when he led MLB in games pitched. The Canadian slinger’s recovery from elbow surgery places him on a late April timeline for his 2025 debut, but it doesn’t seem likely that he’ll step straight into the fire, as the Mariners will want to conserve him for big situations in the heart of the season. Taylor had a good chance to compete for early high-leverage reps in the Spring, but a recently discovered lat injury will see him likely miss all of Cactus League action, and he’s without a timeline for return. Kowar looked likely to win a roster spot on Opening Day 2024 before he needed elbow surgery. He’ll likely return closer to the summer, but there’s no guarantee he can win a role anyhow.
The Mariners also have solid, if unspectacular, group of bullpen incumbents that they’ll rely on for a significant chunk of the early season relief workload. Thornton has been a fixture in the Seattle bullpen since he was acquired as part of an underwhelming 2023 trade deadline and supplanted Paul Sewald on the roster. The bespectacled sweeper thrower struck out more than 1/3 of hitters he faced with no one on base in 2024, but struggled more in inherited runner situations. Bazardo is an interesting case, as he’s only pitched in 32 games with Seattle since that underwhelming 2023 trade deadline, but may or may not have had a soft breakout in late 2024. Returning to the roster on Sept. 1, Bazardo walked just one batter and allowed runs in just one of 11 appearances that totaled exactly 11 innings.
Seattle’s crafty lefties, Speier and Saucedo, both had rocky 2024 seasons, making 2025 make-or-break years for the pair of them. Speier was absolutely lights out in April before tailing off and eventually succumbing to a rotator cuff injury and making seven sporadic appearances after May 27. Saucedo also shined early but got hurt in May on a fluky play. He never found much consistency and had issues with inherited runners, allowing 43% of them to score. The Mariners will need at least one of the two of them to perform with consistency in high-leverage situations this year.
Of the three new, healthy relievers on the 40-man roster, Klein might have the most potential, as he was considered Oakland’s No. 19 prospect by Fangraphs after he was traded by the Royals for Lucas Erceg at the 2024 trade deadline. He posted a video of his most recent live bullpen last week where he hit 100 MPH, and at just 25, he gets the nod for the final spot for me because of upside. Danner and Legumina are the other bullpen lab guys of the moment on the roster, and both are young enough to have upside if they can make something of the opportunity. Danner’s slider was graded a 60 by Fangraphs as a prospect and Legumina bears some resemblance to Sewald in arm slot and repertoire.
Bolton and Vargas are the other incumbents on the 40-man. Bolton popped up with a few decent outings in April and May in 2024, but made just two MLB appearances after May 22. He has MiLB options, but by no means is his 40-man roster spot safe at the moment. Vargas, the intriguing piece of the Eugenio Suárez salary dump, is out of options and improved his erratic walk rate in 2024, but still never saw MLB despite spending the entire year on the 40-man roster. He seems like a likely DFA if he struggles at all in Spring Training.
Of the non-roster guys, I’m most intrigued by Fujinami by far. The Japanese fireballer struggled in AAA with the Mets in 2024 and battled a shoulder injury, but his raw tools popped in his relief stint with the Orioles in 2023, where he posted a 26% strikeout rate, a 10% walk rate and averaged 99.2 mph on his fastball. He spent the Winter making six starts in Puerto Rico, totaling 20.2 innings with a 27% strikeout rate and a 12% walk rate. Maybe he’s nothing, but he has more life in his arm than most of the non-roster cast offs the Mariners usually bring in.
Pomeranz, Hahn and Feliz are all experienced MLB veterans who last appeared in the big leagues in 2021. Does that sound like an intentional bit from the Mariners front office for some laughs or a coincidence? Who can say, really? Similarly, Medina last appeared in MLB in 2022. He spent a year in the KBO before having a solid season in AAA with the Nationals last year. He’s only 28, unlike the other MLB veterans in this group in their late 30s, so he probably has the most upside of the bunch.
Overall roster thoughts
This is a good roster. It’s among the best the Mariners have ever had. It is as good as most rosters in the American League.
The lack of an attempt to take this good roster and make it great is weak and sad. There are clear holes at 1B, 2B, 3B and DH, and the bullpen lacks high-upside arms or relievers with big-game experience. The team did next to nothing to address any of that, swapping out one veteran utility infielder for another, switching Polanco from 2B to 3B, and taking fliers on dozens of DFA fodder guys and veteran bounce back lottery tickets. Dipoto then said they actually didn’t have many holes to begin with.
A modest budget and bad macro environment for trading means the Mariners are stuck in the middle with the other good-not-great rosters in the AL. Most projection systems and gambling sites have them slightly behind Houston and Texas in the West and firmly in the mix for the Wild Card. Seattle has to hope that they play well enough in the first half of the season to justify increased investment when teams will start cherishing their quality prospects again midseason.
Playing variance games as fringe contenders year after year is exactly where Mariners leadership has told fans they’re striving to be. At this point, there’s nothing left to do but hope this bite of the apple tastes better than the last two.
I'm really hoping the Mariners figure out how to maximize Fujinami. That could really be a boon.
Great article, thank you! I think I need to read it again. Also! Are you going to opening day!?!