Houser was recalled from Triple-A Colorado Springs on Sunday.
Houser will take the spot of fellow right-handed bullpen arm Jorge Lopez, who was sent packing to Colorado Springs in a corresponding move. Houser has made two starts in the minors since his last big-league appearance, allowing just two earned runs across 9.2 innings -- both via solo home runs. He'll be a candidate for long relief given that he last pitched June 11, but seems unlikely to pitch in a high-leverage situation.