Players and coaches who witnessed the incident said Nava was feeding balls into a pitching machine as part of routine warmups when GreenJackets infielder Joel Weeks hit a line drive back to the mound that struck Nava squarely in the chin.
Nava was behind an L-screen at the time of the incident, but the ball first bounced off the machine before hitting him.
GreenJackets trainer L.J. Petra attended to Nava until an ambulance arrived.
The 40-year-old hitting coach was alert and awake when he left in the ambulance. After the x-rays revealed no broken bones, he returned to Lake Olmstead Stadium for tonight's game against the Charleston RiverDogs. Nava, normally the first base coach, took the night off and was replaced by San Francisco Giants roving infield instructor Jose Alguacil.