"Braves center fielder Jordan Schafer mentioned in February the potential nightmare of running into right fielder Jason Heyward while pursuing a fly ball in the gap.

Center fielder Nate McLouth lived the nightmare Wednesday night, colliding with Heyward as both sprinted to the gap chasing a fly ball by Arizona's Gerardo Parra in the eighth inning.

McLouth flipped over the much larger Heyward and lay sprawled on the ground as Parra circled the bases for a two-run, inside-the-park home run that sent the Diamondbacks to a 2-1 win at Chase Field.

McLouth left the game and was examined by a doctor. He had a severe headache and was being monitored after the game, but said he had not been tested for concussion. Heyward stayed in and finished the game.

Both players and manager Bobby Cox described the collision as unavoidable, because they said the ball was hit to a spot between the two outfielders that required both to sprint full-out toget it. They arrived simultaneously.

"It's just one of those where neither of us could call it, unfortunately," said McLouth, who was in position to make the catch before seeing Heyward a split-second before the collision.

The ball caromed off McLouth's above the wrist on his glove hand.

"The ball was placed at a perfect spot," said Heyward, who fell to the ground, too, before getting up and chasing the ball to the wall. "It was one of those where you don't really have time to look at each other, you don't really have time to call it. And if you don't go after it – that's one thing you don't want."

McLouth added, "If it falls between you then you look like an idiot, but then if you both make the extra effort for it sometimes that's what happens. It's pretty much unavoidable, I think.... I would have had it, and he probably would have, too. It's just, again, one of those ones where it's impossible to communicate in that situation." "