Mariners Spring Training: 3 storylines that actually matter ahead of 2026

For many, the start of spring training signals the start of the baseball season. Even though the rosters are a mix of veteran big leaguers, fresh-faced prospects, and everyone in between, it's the first time MLB organizations will be facing each other in front of fans.

Ultimately, the standings are entirely irrelevant and spring training is primarily a way for players to get back into the swing of things. Furthermore, based on what the organization sees in the month of games, key roster decisions are made. The Mariners have no shortage of questions heading into the start of the 2026 regular season, and here's how they might play out once Opening Day rolls around.

The infield alignment is still up in the air

The Mariners finished their offseason strong by finalizing a trade to acquire Brendan Donovan. In addition to patching a potential hole in their lineup, they got some much-needed support for their infield, a weak link in last year's roster. But although they know he'll be somewhere on the infield, his exact position isn't yet clear.

He spent the vast majority of last year playing second base for St. Louis, a theoretically easy transition to Seattle given the gap left by Jorge Polanco's departure. However, this would push Cole Young off of the depth chart. Young didn't quite have the rookie season many were hoping for, but he'll need more reps to live up to his lofty prospect expectations.

If that's the case, the only place left for Donovan will be third base, a position he hasn't played for more than 10 games since his rookie year in 2022. The Mariners haven't had the greatest success in the past placing second basemen in the hot corner (Luis Urías, Dylan Moore, and Jorge Polanco all fell short), but Donovan has a decent arm and Seattle has made it work with atypical third basemen like Ben Williamson.

Colt Emerson represents a potential wild card that, assuming he continues his torrid pace through the minor leagues, could present new problems, albeit good ones to have. An infield logjam isn't exactly something one may have anticipated for a team who has lacked franchise talent in the area for years, but it's the result of two great things: aggressive moves by the front office and the blossoming of young talent.

Who will be the primary starter in right field?

The Mariners entered 2025 with a rock-solid outfield trio, but after an underwhelming start and Victor Robles' gruesome shoulder injury, responsibilities in right field were split amongst several players. Dominic Canzone got the lion's share and made the most of it, posting a 131 wRC+ across 68 games in the position. Before he became the team's backup, Seattle also unsuccessfully tried deploying Leody Taveras, Luke Raley, and even Samad Taylor.

Robles has returned but not to the level he reached in 2024. To further complicate the issue, the Mariners signed platoon specialist Rob Refsnyder to a one-year deal and based on comments from Justin Hollander, the plan is to use a four-man platoon.

It's doubtful that all four options (Raley, Canzone, Robles, and Refsnyder) will split playing time perfectly evenly, so there must be one name that becomes Dan Wilson's go-to option in the lineup. The organization won't have enough conviction on who that is until taking some time to workshop some arrangements, but for now the job is still for the taking.

Can the Mariners avoid major injury losses?

Seattle had plenty of players hit the injured list in 2025. Robles and Ryan Bliss both missed significant time, but luckily weren't expected to play crucial roles. On the other hand, Logan Gilbert, George Kirby, and Bryce Miller all spent meaningful time on the injured list.

Health is a necessary condition for any team to find success in the regular season and playoffs. It's unreasonable to expect any roster makes it through a grueling baseball season without a couple of their best players going down, but at this point in their competitive window, the Mariners can't afford to lose crucial resources like starting pitchers for weeks at a time.

With several of their best players competing in this year's World Baseball Classic, minimizing injury risk will be even more crucial. It goes without saying that a month or two without Cal Raleigh, Julio Rodríguez, or Randy Arozarena could be the difference between a championship run and spending October at home.