SEATTLE -- Before Wednesday's game, the Seattle Mariners swapped one struggling first baseman with injury problems for another.

Justin Smoak, who had just one hit in 18 June at-bats, was placed on the 15-day disabled list due to a sore left quadriceps. The move came as Logan Morrison was finishing up his rehab stint at Triple-A Tacoma following a hamstring injury that landed him on the DL in April.

Morrison will effectively become the Mariners' starting first baseman, despite the .125 batting average he carries after going 0-for-4 Wednesday in Seattle's 4-2 loss to the New York Yankees. Smoak was hitting just .208 after a horrible start to June.

Smoak's injury, while seemingly convenient as far as the roster makeup, comes at a bad time for the Mariners. Seattle remains desperate to find a designated hitter to fill in for injured Corey Hart, and Morrison could have provided help on that count. Instead, the Mariners will need him to fill an everyday role while Smoak recovers.

Morrison also is another left-handed bat in a lineup that is southpaw-heavy.

Smoak was one of the bright spots in the Mariners' offense for the first two months of the season but fell into a June swoon. The switch hitter has seven home runs, tied for second on the team.

The Mariners don't necessarily need Smoak back in the lineup to have offensive success, but they sure would like the Smoak of April and May to return after his DL stint is over.