As a 2010 second round draft pick for the Atlanta Braves, Simmons began his first full professional season in 2011 with the Hillcats as the team's starting shortstop. Drafted for his glove and arm at first, Simmons was motivated to show what he could do at the plate. While batting primarily first or second in the order, Simmons led the Carolina League in hits and at-bats, and captured the batting title with a .311 clip. He was the only qualifying hitter to bat over .300 in the league. His 35 doubles placed second in the circuit.