Freeman is batting .299 with 12 homers and 41 RBIs. He left Wednesday's game against Boston in the seventh inning, and the move was made retroactive to the following day.
An MRI on Monday did not reveal a more serious injury.
"Just a contusion," Braves manager Fredi Gonzalez said. "Hopefully, we get him back sooner than later."
The two-time All-Star played in at least 147 games in each of his past four seasons in the majors, including all 162 in 2014.
Freeman is 13-for-25 in six games this season against Washington, which hosts Atlanta in a three-game series that started Tuesday. The Braves entered the series two games behind the NL East-leading Nationals.
"We'll figure it out," Gonzalez said of his lineup. "We didn't have him the whole weekend series against the Mets, and we won three."
Atlanta recalled outfielder Joey Terdoslavich from Gwinnett of the Triple-A International League.