Colt Emerson might be one of the best prospects in baseball, but that does not mean he needs to be on the Seattle Mariners’ Opening Day roster. A consensus top-10 prospect on every list released since the start of 2026, Emerson is one of the most complete and well-rounded players to come through the Mariners’ farm system in years. He will play an important role for Seattle in 2026.
However, given the hype not only from prospect circles but also from his own front office, it would still come as a surprise to see Emerson back with their Triple-A affiliate, the Tacoma Rainiers. This is not because of a sudden lack of belief, and Emerson can still make the final 26-man Opening Day roster; that is a real possibility. But because of their roster construction, it makes sense for Emerson to start the season, at least, from the outside looking in.
Colt Emerson May Miss the Mariners’ Opening Day Roster
Right-Handed Problems
Following the huge addition of Brendan Donovan, the Mariners’ three everyday infielders, Donovan, J.P. Crawford, and Josh Naylor, are all left-handed hitters. On the surface, that is not necessarily a problem. None of these veterans are strict platoon players, and their splits do not collapse when a left-handed pitcher is on the mound.
Seattle’s top two prospects, Cole Young and Emerson, battling for the final spot, are also left-handed hitters. The Mariners showed last year they were reluctant to expose Young to elite left-handed pitching, and that line of thought is likely to continue in 2026 as they build confidence in their prospects. When your everyday core already leans left-handed, carrying two rookie left-handed bats not only limits flexibility but also hurts their development. With three infield spots already set, there is no room to start both. At this stage, they need as many reps as possible, and having the two rotate would only do more harm than good.
That makes switch-hitting Leo Rivas close to a lock. With platoons already set in right field and at designated hitter, there is simply not the space to carry both Young and Emerson unless they go with only seven arms in the bullpen — something the Mariners have never done before. Allowing both Emerson and Young to develop is essential at this stage of their careers, and while pitching matchups matter, roster flexibility and long-term development matter more.
Why Tacoma Makes Sense
The Mariners’ front office has continued to fuel the Emerson hype train all offseason. Executive of Baseball Operations Jerry Dipoto even said, “It’s not out of the question he earns the spot on the team… I think he knows that. Colt’s confident.” On the surface, sending him to Tacoma after that would feel counterintuitive.
As players report to spring training, Donovan appears to be working at third base, increasing the likelihood he opens the season there with Young at second. That alignment gives Seattle something valuable: time. Time for Donovan to settle into a relatively new position without the pressure of a midseason adjustment. Time to evaluate how the platoons shake out, and time to let Young build on his big league experience.
Colt Emerson, tunnel vision. @MLBPipeline’s No. 9 overall prospect unloads during his final round of BP on the velo machine here on the backfields in Peoria. pic.twitter.com/whD4hy31uy
— Daniel Kramer (@DKramer_) February 12, 2026
It also allows Emerson to get consistent reps at third base in Triple-A, away from the spotlight. Prospects like Emerson and Young must play every day. Carrying one to sit on the bench and play backup would harm their development far more than getting valuable reps at Triple-A, especially when getting to grips with a new position. Emerson has primarily played shortstop, and a smooth defensive transition is much easier in April in Tacoma than in July in Seattle. Rather than forcing multiple moving parts at once, the Mariners can stagger them. This allows their prospects to develop, and gives the Mariners the luxury of time to assess their options.
An Early Promotion
Emerson could still be on the team by May. They will have a better feel for the other platoons. Donovan can move to the outfield if Luke Raley or Victor Robles are not working, and Emerson can fill that spot. If Young struggles, he can go down to Tacoma, and Emerson can take his place. They would then be in a much stronger position to assess their squad and adjust accordingly. There is no doubt the Mariners believe Colt Emerson is ready to start the Opening Day if needed, and he likely plays a very important part in their 2026 season. But for now, it looks like that chance may have to wait, if only for weeks rather than months.
Main Photo Credit: © Allan Henry-Imagn Images