Hamilton had been sidelined since he hurt his right shoulder while diving for a ball on Aug. 18. He had a three-game rehab stint. Hamilton leads the majors with 54 stolen bases in 61 attempts, two shy of his mark from last season.
The Reds also activated outfielder Brennan Boesch off the 15-day disabled list on Tuesday. He had been sidelined with a sprained right ankle. In addition, Cincinnati called up left-hander Tony Cingrani, left-hander Brandon Finnegan, right-hander Josh Smith and utility player Kristopher Negron from Triple-A Louisville.