Immediately after the conclusion of his college hockey career, Milbury played in five games with the Boston Braves, the Bruins' top farm team, in 1974. He signed with the Bruins as a free agent on November 5, 1974, and spent the next two campaigns with the Rochester Americans, the team's new American Hockey League (AHL) affiliate. In both seasons he led the club in penalty minutes with 246 in 1975 and 199 in 1976, finishing fourth and third respectively in the AHL.