Kjerstad is out of the lineup for Wednesday's game against the Yankees.
Kjerstad had occupied the designated-hitter spot in each of the previous three games and started five of the past six contests overall, but he'll likely move into more of a part-time role following Ryan Mountcastle's reinstatement from the injured list Tuesday. Mountcastle and O'Hearn will serve as the Orioles' first baseman and designated hitter, respectively, Wednesday and are expected to occupy either lineup spot in some fashion more often than not heading into the postseason.