SAN FRANCISCD -- Orioles right-hander Darren O'Day, who felt discomfort in his right shoulder while pitching in Oakland on Thursday, was sent to Baltimore to have his shoulder tested and will miss the series with the San Francisco Giants.
O'Day, who returned from a right hamstring strain July 24, received a cortisone shot.
"It was as sore today as it has been," Orioles manager Buck Showalter said before Saturday's game against the Giants. "He was injected and we may have him serve time on the DL to get it resolved."
O'Day's absence will give a handful of other relievers the chance to pitch in high-pressure, late-game situations.