The Seattle Mariners have one of the best farm systems in baseball and several prospects will likely make their way to the majors in 2026.

Top 100 prospects Colt Emerson, Michael Arroyo and Lazaro Montes are all expected to make their major league debuts in the coming season, according to MLB Pipeline.

Assuming all three players perform and earn the confidence to be every day starters, Montes and Emerson's respective timelines likely mean they'll be full-time starters in 2027.

Shortstop J.P. Crawford will become a free agent after the '26 season. The expectation is that Emerson, the Mariners' top prospect, will take over at shortstop when Crawford's contract ends.

Montes is expected to be the team's right fielder of the future, though some publications project him more as a designated hitter.

Seattle's 2025 Opening Day right fielder, Victor Robles, will have a team option for 2027 that the M's can decline to make room for Montes.

The Mariners recently made a decision to move Arroyo from second base to left field.

On the surface, the move made sense strictly from a surplus perspective. Cole Young, who made his major league debut in 2025, plays second base and the team also has Ryan Bliss, another second baseman, on the roster. He won't enter his first year of arbitration until 2028.

But if you look deeper than that, perhaps the Arroyo decision has more nuance to it.

Randy Arozarena has been the team's starting left fielder since the Mariners acquired him in a trade with the Tampa Bay Rays on July 26, 2024. This past season, he made the All-Star Game as a replacement for teammate Julio Rodriguez.

Arozarena scored 95 runs in 160 games, and hit 32 doubles, a triple and 27 home runs with 76 RBIs this season. He also stole 31 bases on 37 attempts. He slashed .238/.334/.426 with a .760 OPS. His homers set a new single-season career-high and his steals were the second most in a single season in his career.

Arozarena is set for his fourth year of arbitration in 2026 and is estimated to earn $16 million, according to Spotrac, and he's a free agent at the end of the season. Perhaps Arroyo will be prepared to take his spot in 2027 also.

Arroyo isn't the first case of Seattle testing out a top 100 prospect in left field.

In 2024, the Mariners had catcher Harry Ford play several games in left field before ultimately choosing to keep him at catcher. He's expected to be the backup to Cal Raleigh in 2026.

Arroyo's move to left field isn't necessarily a death knell in Arozarena's tenure in Seattle. If Arroyo fails to perform in the outfield, the Mariners can choose to keep him at second base or package him in a future trade and extend Arozarena.

There is certainly a chance that the experiment with Arroyo in left field doesn't stick. He played all of 2025 with the High-A Everett AquaSox and Double-A Arkansas Travelers as a second baseman and designated hitter. He spent parts of 2023 and '24 at shortstop between the rookie-ball Arizona Complex League, Single-A Modesto Nuts and Everett and briefly tried out third base when he played in the Dominican Summer League.

This past season, which began with the AquaSox and ended with the Travelers, Arroyo scored 78 runs in 121 games, and hit 24 doubles, a triple and 17 homers with 54 RBIs. He slashed .262/.401/.433 with an .834 OPS.

Considering how the Mariners have positioned other prospects to potentially take over starting roles in 2027, it makes sense to infer that's what the organization is trying to do with Arroyo.

If that's the case and Arroyo is solid in left field, 2026 might be Arozarena's last season in the Pacific Northwest. 

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