The Orioles recalled left-handed reliever Donnie Hart from Triple-A Norfolk in advance of Friday's game against the Red Sox in Boston.
Hart takes the place of right-hander Yefry Ramirez, who was optioned to Norfolk after Wednesday's 5-3 win against the Blue Jays.
Hart, 27, appeared in 51 games for Baltimore last season and went 2-0 with a 3.71 ERA in 43 2/3 innings. He pitched 3 2/3 scoreless innings in three games for Norfolk prior to his recall.