First baseman Logan Morrison and utility player Brad Miller headline the deal, which also sees Seattle pitcher Danny Farquhar headed to Tampa. In exchange, the Mariners will receive starting pitcher Nathan Karns, reliever C.J. Riefenhauser and outfield prospect Boog Powell.
Morrison can play outfield as well as first base, and figures to move positions in Tampa Bay as James Loney holds the starting job at first base. The 28-year-old hit .225 with 17 home runs and 54 RBIs this season.
Miller played 144 games in his third season with the Mariners, hitting .258 with 11 home runs and 46 RBIs.
Karns is the biggest name headed to the Mariners. The 27-year-old made 26 starts for the Rays in 2015, going 7–5 with a 3.67 ERA and 145 strikeouts.