The Nationals optioned Bird to Triple-A Rochester following Tuesday's 3-1 loss to the Rockies.
Bird pitched a scoreless inning Tuesday, bringing his ERA down to 5.35 through 38.2 innings on the season, but the Nationals will send him down to Rochester to make room in the bullpen for right-hander Luis Perales, who will be recalled from Triple-A on Wednesday. Bird could still return to Washington later in the season to provide the parent club with a fresh arm, but he would likely be limited to middle-relief duty.