OAKLAND -- The A's promoted prospect Matt Olson on Sunday, rewarding the first baseman for his ongoing production at the plate, where he's belted 14 home runs in 47 games for Triple-A Nashville.
Right-hander Daniel Mengden, charged with four runs in 4 2/3 innings against the Nationals on Saturday, returned to Nashville to make room for Olson, who was scheduled to arrive at the Coliseum just ahead of game time.
Mengden's departure paves the way for the return of right-hander Jesse Hahn, who is set to come off the disabled list Tuesday for a start against the Blue Jays, A's manager Bob Melvin announced.