Struggling center fielder Leonys Martin was designated for assignment by the Mariners on Sunday, two days after he was benched by the team.
In a corresponding move, the Mariners recalled first baseman Dan Vogelbach from Triple-A Tacoma. He is expected to platoon at first base with Danny Valencia going forward.
Valencia, 32, has struggled as the full-time first baseman. After he went hitless Saturday, he had a .145 average. The right-handed-hitting veteran has no home runs and four RBIs in 69 plate appearances. The left-handed-hitting Vogelbach, 24, was hitting .309 with two home runs and 14 RBIs in 66 plate appearances for Tacoma.
In another move, the Mariners sent right-handed reliever Chase De Jong to Tacoma and recalled right-handed reliever Chris Heston in his place.
The left-handed-hitting Martin has struggled this season, hitting .111 with no home runs or RBIs in 58 plate appearances.
Jarrod Dyson replaced Martin as the Mariners' starting center fielder, moving over from left field. Rookie Guillermo Heredia is expected to start in left field going forward.
Martin, 29, had 576 plate appearances last season, starting 142 games in the outfield for the Mariners. He set career bests with 15 home runs and 47 RBIs. Seattle acquired him in a 2015 trade with the Texas Rangers.
The Mariners are in last place in the AL West with a 7-12 record.