The Mariners are finalizing a deal to acquire St. Louis Cardinals infielder/outfielder Brendan Donovan in a three-team deal involving the Tampa Bay Rays, sources with knowledge of the deal have told The Seattle Times.

The framework of the deal has been finalized, but the teams are still in the process of reviewing medical information and notifying players, sources said.

Donovan, entering his age-29 season in 2026, was a first-time All-Star in 2025, and he won a utility player Gold Glove as a rookie in 2022.

In four seasons in St. Louis, Donovan has had a career slash line of .282/.361/.411 (. 772 OPS) with a 117 OPS+ (17% better than league average), 40 homers, 97 doubles and a 11.1 bWAR.

Donovan, who is in his second year of arbitration eligibility, agreed to a $5.8 million contract for 2026 with the Cardinals. The Mariners will have two total seasons of club control with Donovan becoming a free agent after the 2027 season.

He has a career on-base percentage of .361, making him a leading candidate to bat at the top of the Mariners lineup.

The top five hitters in the Mariners lineup — Donovan, Julio Rodríguez, Cal Raleigh, Josh Naylor and Randy Arozarena — have been All-Star selections in the past two seasons.

Donovan’s 13% strikeout rate in 2025 was among the lowest in MLB, and his 119 wRC+ ranked fifth among regular MLB second basemen.

Per FanGraphs’ metrics, Donovan had a higher fWAR (2.9) in 2025 than Jorge Polanco (2.6), the middle-of-the-order slugger the Mariners just lost to the New York Mets in free agency.

This story will be updated.