The move was retroactive to Tuesday. Reyes will be examined by team doctors on Friday in Atlanta.
Taking his place on the roster is left-hander Mike Dunn from Triple-A Gwinnett. Dunn threw 3 1/3 scoreless innings in two appearances for Gwinnett.
Dunn pitched in six games with the Braves in spring training, with a 1.42 ERA and 6 1/3 innings.