Braun reached on a fielder's choice and scored from first base on Prince Fielder's double in the top of the seventh inning, then played the bottom half of the frame in the outfield without a ball hit his way.
"It looked like he scored from first with no problem, but the trainer came over to me and said, 'He says it's tightening up but he's going back out there,'" Macha said.
The next half-inning, Macha made a change. Braun was replaced in the top of the eighth by pinch-hitter Jody Gerut, who flew out to end the inning and then remained in the game as the left fielder.
Back issues first became a problem for Braun last season, when a strained muscle between his ribs sapped his power stroke down the stretch. The issue returned in Spring Training, but Braun has mostly been able to play through it, starting all but three of Milwaukee's games in left field.
Braun went 2-for-4 with two runs scored and an RBI on Wednesday and is among the National League's top 10 with a .321 batting average, 49 runs scored and 48 RBIs.
Adam McCalvy is a reporter for MLB.com.
This story was not subject to the approval of Major League Baseball or its clubs.