The child, who suffered a cut to the head, was listed in stable condition, Capt. Mark S. Camp said.
According to Camp, the incident happened in the Martin Luther King Drive area. The child was in a front yard when someone in a vehicle backed out of the driveway and knocked the child under the car.
The cut was severe, and the child was taken by air ambulance to an Atlanta hospital, Camp said.
The relationship between the child and driver is unknown. Police had no further information at the time.