NEW YORK -- Prior to Tuesday's game against the Mets, Martin Prado was listed as a game-time decision. Perhaps a first-inning decision would have been more apt.

Prado's return to the starting lineup lasted just a half-inning. After popping out in his first at-bat, Prado did not take the field with his Braves teammates. Instead, Adam LaRoche -- who had been in manager Bobby Cox's alternate lineup in case Prado was unable to start -- manned first base.

When Prado fouled off a ball in that at-bat, Cox explained afterward, he endured a sudden recurrence of the headaches that have bothered him all week. And so the Braves flew him back to Atlanta for further tests, which could possibly result in a stint on the disabled list.

"We thought he was good today," Cox said. "He had a good batting practice, took ground balls, and the first at-bat, he swung and fouled a ball and it reared up again. We're not going to disable him right now. We'll send him back to Atlanta, run some more tests and see where this thing's coming from. So far, we haven't found anything."

Prado originally left Saturday's game in the sixth inning with what the Braves diagnosed as heat-related problems, and the team has exercised caution with him ever since. Prado pinch-hit Sunday and drew a walk, but sat out Monday's game when he continued to suffer from headaches.

Yet Prado had not suffered any headaches Tuesday as of roughly 4 p.m. ET. He took batting practice with his teammates and fielded ground balls, and -- having passed those tests -- began the game in the starting lineup.

"Let me tell you, I felt better," Prado said before the game. "I didn't have headaches like I did the last two days, and that's a good thing. I went all day without a headache, which is good."

Certainly, the Braves were also eager to have Prado back, considering his .309 average and eight home runs in 92 games.

"He's made our team go," Cox said. "He's one of the big guys."