But after a few hours of treatment, the ankle was feeling much better than it did just a few hours earlier, when he aggravated it moving back from a Bronson Arroyo pitch.
"He goes through all these tests right now, and you'd never know he had a bad ankle," manager Bobby Cox said. "He can do everything. I don't know what happened."
Seeing Renteria last just one pitch during his return to the lineup is certainly something the Braves didn't envision. The high right ankle sprain that he'd suffered on Aug. 2 had seemingly improved greatly over the course of the past few days.
Although Renteria wanted to return on Monday, after he'd successfully maneuvered through figure-8 drills, Cox exercised his usual caution. Then, after seeing his veteran shortstop take batting practice, field grounders and run the bases without any setback, he opted to activate him.
Unfortunately, the only motion that wasn't perfectly simulated was the one Renteria made while moving back from that pitch.
After Renteria stumbled and attempted to keep his weight off his right leg, Cox and head athletic trainer Jeff Porter rushed onto the field. It took them just a few moments to decide they had to help Renteria back to the bench.
"I stayed back, and I think I put weight on my ankle, and it just popped," said Renteria, who walked without much of a limp before addressing the media after the Braves' 4-2 loss.
Obviously, hearing a pop isn't good, and in Renteria's best-case estimation, he likely won't be available to play again until some time next week.
"I've still got a little pain, and it feels a little weak," said Renteria, who is hitting .336 on the season and .398 in the 20 games he's played since the All-Star break.
While Renteria is out, Yunel Escobar will once again serve as Atlanta's everyday shortstop. To open a roster spot for Renteria on Wednesday, the Braves had optioned Martin Prado to Triple-A Richmond. Because of this injury, Prado won't have to wait 10 days before being recalled.
With rosters expanding on Sept. 1, the Braves won't have to put Renteria on the disabled list if they feel he'd definitely be ready before Sept. 7, which would be his eligible date for activation.
But given this setback and the need to play with a full roster, they may be forced to wait another two weeks before once again giving him the opportunity to return.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.