The Yankees made the moves before Saturday's game against the Los Angeles Angels. The Angels routed the Yankees 13-1 on Friday night.
The 30-year-old Leroux has pitched 63 games for Pittsburgh and the Marlins in the past five seasons. He was 0-2 for Scranton/Wilkes-Barre this year before the Yankees signed him to a major league contract and selected him from the minor league roster.
Greene made his big league debut Thursday at Boston. He allowed three unearned runs while getting one out and walking three.
The Yankees also released minor league lefty Nik Turley and said minor league righty Jose Campos had undergone Tommy John surgery.