Coach Brian Kelly tells the South Bend Tribune both players have been cleared to participate in all workouts. He spoke Monday at a charity event.
Rees, who is part of a four-player competition to start at quarterback, faces four misdemeanor charges after being arrested following a South Bend, Ind., party on May 3.
He faces a July 17 hearing on a charge of battery, two counts of resisting law enforcement and one count of illegal consumption of alcohol by a minor.
Calabrese is charged with one count of misdemeanor intimidation for allegedly threatening a police officer. His next hearing is set for Aug. 20.