Mariners Promote Colt Emerson, Brendan Donovan To IL

The Mariners are expected to bring up top prospect Colt Emerson to the big-league squad, reports Ryan Divish of the Seattle Times. The 20-year-old shortstop is among the highest-ranked young players in the sport. The team has officially announced the move. Brendan Donovan was placed on the 10-day IL with a groin strain as the corresponding move.

The Mariners released an updated lineup for Sunday Night Baseball against the Padres. Emerson is now batting ninth and playing third base instead of Leo Rivas. He’ll be the youngest Mariner to make his debut since 19-year-old Félix Hernández in 2005, according to the team.

Emerson fell short of an MLB gig out of Spring Training, despite a 111 wRC+ in 18 games. The 20-year-old has slashed .255/.347/.469 through 38 games at Triple-A this season. He’s popped seven home runs to go with 10 stolen bases.

Seattle inked Emerson to an eight-year, $95MM extension in late March. The price tag is a record figure for a player who has yet to appear in the majors. MLB Pipeline has Emerson ranked sixth among all prospects. FanGraphs has the infielder just outside the top 10.

The Mariners didn’t give Emerson an opportunity in the majors when shortstop J.P. Crawford was working through a shoulder injury early in the year. It would seem another injury to an infielder has opened the door for the youngster. Donovan had been out of the lineup since Friday. He’s been the club’s everyday third baseman when healthy. Emerson has played mostly shortstop with Tacoma, but he’s made five starts at the hot corner this season.

Donovan has dealt with groin issues since the offseason. He underwent sports hernia surgery before the 2026 campaign got underway. The infielder hit the IL in late April with a groin strain. After just seven games, Donovan is back on the injured list with the same injury. With Emerson taking over at third base, the versatile Donovan will move around to multiple spots when healthy, per Adam Jude of the Seattle Times.

Seattle took Emerson with the 22nd overall pick in the 2023 draft. He moved quickly through the lower levels of the minors. Emerson posted an impressive 129 wRC+ across three levels last year, capped off by a massive .364/.444/.727 line in a brief sample at Triple-A. He hasn’t been as dominant so far this season, particularly in terms of contact. Emerson has a career-high 27.2% strikeout rate over 169 plate appearances in the minors this year. The power and speed have been among the best he’s shown, though. Emerson’s 16 homers and 14 steals in 2025 were both career highs. He would’ve blown past those marks if he had stayed with Tacoma much longer.