Mariners Projected 2029 Roster: Lineup, Rotation, Bullpen, Bench

2026 Top 50 Mariners Prospects

Despite the trades of two Top 10 and four Top 20 prospects over the winter, the Seattle Mariners again boast one of the best farm systems in baseball to start 2026. The club’s success in the draft and efforts in Latin America are keeping the organization stocked with a mix of upside, probability, proximity, and balance.

Baseball ThingsJason A. Churchill

In this exercise, we project three years into the future to piece together a roster. But there’s a catch: No trade acquisitions, free agent signings, or contract extensions allowed. This is what the roster might look like if the club simply let everything play out for 2029.

To illustrate how much it can change from year to year, here’s the projection from last year.