"Everything was normal until I backed away from the plate and the back of my head started pounding," Heyward said. "It started running up to the top of my head. I tried to shake it off, but it didn't happen.
"It was just kind of like a full-on instant headache and pounding. It started in the back of my head and then just kind of worked its way up. It was hurting me, pounding the whole time I was on the field."
The Braves have diagnosed Heyward with a strained neck muscle and placed his status as day to day. While Heyward is hopeful to play in Wednesday's series finale, he understands manager Fredi Gonzalez and the team's medical staff will choose to take the cautious approach.
Heyward was still feeling a slight headache when he spoke to reporters after the game.
"I feel better than I did when it happened," Heyward said. "But I'm just going to see how I'm feeling tomorrow. The doctor said it was calming down once he came to see me. I agreed with him. I'm just going to get some medicine and get it calmed down."
Heyward was feeling good enough to come back on the field when the benches and bullpens emptied after Julio Teheran hit Bryce Harper with a pitch in the fifth inning. Nothing but words were exchanged.
"It's an unwritten rule," Heyward said. "It's part of the game of baseball and competition. You want to be out there for your teammates. Everybody does. So that's just the way that goes."
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.