First baseman Justin Smoak is off the Seattle Mariners' disabled list and headed to Triple-A.

The Mariners demoted him Friday after he missed almost a month of the season with a strained quadriceps. At the time of the injury, Smoak was struggling at the plate with a .208 average, seven homers and 29 RBIs in 63 games. He was batting only .191 in his last 56 games.

In four seasons with the Mariners, the 27-year-old has a .227 career batting average with 67 home runs and 204 RBIs.

The Mariners plan to continue to use Logan Morrison at first base and Dustin Ackley and Michael Saunders in the outfield. Corey Hart will serve as the designated hitter.