The moves were made Friday before their game at Chicago.
Right-hander Ervin Santana was reinstated from the disabled list, and the contracts of outfielder Darin Mastroianni and catcher Juan Centeno were selected from Rochester. Santana, who had a back strain, will start Saturday against the White Sox.
Neither Mastroianni nor Centeno were on the 40-man roster, so O'Rourke and Graham were cut to make room. They could accept a minor-league assignment.
Murphy had only three hits in 40 at-bats.