Maldonado, 32, posted a .225/.376/.351 slash line with nine home runs over 119 games last season, splitting time between the Los Angeles Angels and Houston Astros. The backstop notably won a Gold Glove award as a member of the Angels back in 2017.
The eight-year veteran owns a lifetime .639 OPS and spent the first six seasons of his career with the Milwaukee Brewers.
Earlier this offseason, the Mariners traded catcher Mike Zunino to the Tampa Bay Rays, leaving a vacancy behind the dish. However, the club eventually acquired Omar Narvaez from the Chicago White Sox.