SEATTLE -- The Mariners have finally reeled in that coveted bat to round out their 2026 lineup.
The club on Monday was in the process of acquiring infielder/outfielder Brendan Donovan from the Cardinals as part of a three-team trade that includes the Rays, multiple sources told MLB.com, though the transaction has not yet been publicly confirmed or announced by the teams.
The full trade details were not immediately known, but Seattle is trading away three players, per source: pitcher Jurrangelo Cijntje (the Mariners' No. 7 prospect) and outfielder Tai Peete (No. 11) to St. Louis and infielder Ben Williamson to Tampa Bay.
In Seattle, the acquisition essentially ends a staring contest with St. Louis that had extended for much of the offseason, as Donovan had long been a top priority for the Mariners’ front office, but it had not been able to reach a price point with the Cards on a return package.
St. Louis, meanwhile, has been in the midst of a roster overhaul under new president of baseball operations Chaim Bloom, with Donovan being his best trade asset among an offseason selloff that’s already included veterans Nolan Arenado, Willson Contreras and Sonny Gray.
Donovan, 29, is expected to be immediately injected near the top of the Mariners’ lineup, and he gives manager Dan Wilson even more versatility with his defensive alignment.
A first-time All-Star in 2025, Donovan has primarily been a second baseman over his four-year career (225 games), but he also has experience at first base (30 games), third base (46), shortstop (14), left field (163) and right field (30). He was the first rookie in Cards history to win a Gold Glove Award in 2022.
Donovan’s bat, however, is just as much why the Mariners were interested in acquiring him. In four seasons with the Cardinals, he slashed .282/.361/.411 (.772 OPS) with 40 homers, 97 doubles, five triples and 202 RBIs -- good for 10.1 wins above replacement, per FanGraphs, and 119 wRC+ (league average is 100). He’s also sported a 13.5% strikeout rate that was MLB’s 15th-best among 306 qualified hitters in that span, making him an ideal contact specialist at T-Mobile Park, one of the sport’s least friendly hitter environments.
Cijntje was the Mariners' first-round Draft pick in 2024, when he was taken 15th overall as an ambidextrous switch-pitcher out of Mississippi State, though Seattle just announced on Friday that the club was going to focus on the 22-year-old as a right-hander for the near future.
Peete was the 30th overall pick in the 2023 Draft, and he's put up a .724 OPS in 264 Minor League games, topping out at High-A last season.
Donovan avoided arbitration last month by agreeing to a deal for 2026 worth $5.8 million, according to a source, and he will remain under club control for the next two seasons.
In the Mariners’ eyes, that’s precisely why Donovan is an ideal bridge to the club’s younger infielders and within their long-term plans -- even with the departure of Williamson, whose void could open up an even clearer path to an Opening Day roster spot for Colt Emerson, MLB Pipeline’s No. 9 overall prospect.
Mariners general manager Justin Hollander reiterated conviction in Seattle’s young infielders -- Emerson, second baseman Cole Young and Williamson, before being dealt -- as recently as Sunday during FanFest at T-Mobile Park. Yet, for a team that came eight outs shy of its first World Series last October, there was also the reality that its title window is firmly open, and that its roster needed one more proven bat.
The club brought back first baseman Josh Naylor (five-year, $92.5 million contract on Nov. 17) at the offseason’s outset, but had since lost Jorge Polanco (two-year, $40 million contract with Mets on Dec. 16) and Eugenio Suárez (one-year, $15 million agreement with Reds on Sunday) from the 2025 core.
Donovan now gives Seattle’s lineup a whopping five All-Stars from the previous two seasons, along with Naylor, Julio Rodríguez, Cal Raleigh and Randy Arozarena.
The Mariners’ avenue to acquire Donovan opened wider over the weekend, after the Giants -- who were prominently linked to him in trade talks -- pivoted and agreed to terms with three-time batting champion Luis Arraez on a one-year, $12 million deal to play second base. But there were even more teams interested in him earlier this offseason, before St. Louis began its significant sell-off.
As for the Rays’ presence, Monday’s transaction marks the 16th between Seattle and Tampa Bay since Mariners president of baseball operations Jerry Dipoto took over in the 2015-16 offseason.