The Orioles transferred O'Neill (shoulder) to the 60-day injured list Saturday.
O'Neill was placed on the injured list Aug. 26 due to his strained right rotator cuff, so moving to the 60-day IL will officially rule him out for the rest of the year. The 31-year-old will close out his second season in Baltimore with a .212/.300/.377 slash line to go with 10 homers, 23 RBI and 31 runs scored across 260 plate appearances. His 40-man roster spot will go to Felix Bautista (shoulder), who came off the 60-day IL on Saturday.