O'Neill is out of the lineup for Monday's game against the Blue Jays.
He will give up his spot in the starting nine to Coby Mayo, who will step in at first base while Ryan O'Hearn occupies the designated-hitter spot. O'Neill had started in each of the Orioles' previous four games, during which he went 7-for-13 with three home runs, one double, three walks, six RBI and six runs.