Passan reports that trade is a three-way deal also involving the Tampa Bay Rays. The return for the Cardinals and Rays was not immediately known.
Donovan, 29, was one of the Cardinals’ most consistent hitters in 2025, slashing .287/.353/.422 with 10 home runs, 32 doubles and 50 RBIs in 118 games.
A four-year MLB veteran, Donovan has been something of a Swiss Army Knife throughout his St. Louis tenure.
In his rookie season, he won the NL Utility Gold Glove and has experience playing at every defensive position other than pitcher, catcher and centre-field.
Donovan is under team control for the next two seasons and is arbitration eligible for the first time this off-season. MLB Trade Rumours projects he will earn $5.4 million this season.
The move continues an off-season of selling by the Cardinals. The team has already traded star third baseman Nolan Arenado to the Arizona Diamondbacks and veteran starter Sonny Gray to the Boston Red Sox.
Donovan will likely slot in at third base for the Mariners after slugger Eugenio Suarez departed the team in free agency. Suarez agreed to a one-year deal with the Cincinnati Reds on Sunday after helping the Mariners reach Game 7 of the ALCS last season.
