The Reds activated Greene (groin) from the 15-day injured list Wednesday.
In a corresponding move, the Reds optioned Sam Benschoter to Triple-A Louisville. Greene hasn't pitched since June 3 due to a strained groin but will return for the finale against the Phillies. He's also dealt with back issues this season, making a total of 11 starts and registering a 2.72 ERA, 0.97 WHIP and 73:14 K:BB across 59.2 innings. He went 5.1 innings and threw 79 pitches in his latest rehab start last Friday.