Mountcastle was removed from Saturday's matchup versus San Francisco after appearing to hurt himself while diving into second base on a hit, Roch Kubatko of MASNSports.com reports.
Mountcastle got the start at DH on Saturday -- just his second start over Baltimore's past four games -- and doubled in his first at bat in the bottom of the second inning, However, he stumbled while running to second base and appeared to hurt himself while sliding into the bag. Mountcastle was subsequently removed, and Dylan Beavers entered as the pinch runner. Details about Mountcastle's injury should emerge during or after the contest.