Mountcastle (wrist/forearm) was reinstated from the 10-day injured list Saturday.
Mountcastle had been sidelined since May 11 due to a left wrist forearm strain, but he'll serve as the designated hitter and bat fifth Saturday. Prior to his absence, the 25-year-old hit .268 with four homers, three doubles, 16 RBI, 10 runs and two stolen bases over 28 games to begin the year.