Freeman had a similar injury during the beginning of the 2013 season, when he missed 13 games and also hit the disabled list. The Braves are optimistic this won't be a prolonged issue because of where the strain is located.
"It's not a high oblique," Gonzalez said. "My understanding is if it's higher, closer to the rib, it could be a prolonged thing. His is a little bit lower. He had something similar in 2013 early in the season. So we're hoping it's kind of the same type grade."
Freeman had played 10 games since returning from a DL stay for a sprained right wrist. He batted 7-for-38 (.184) with two home runs in that span.
"He's a competitor, a big-time competitor," Gonzalez said. "It's an injury, if treated right, if it's not a serious one, you can get him back in two weeks or three weeks.
"I'm sure he wants to finish the season healthy -- we want him to finish the season healthy. He's a guy who's going to be with us for a lot of years, and we want to win as many games as we can. And he's an important piece in that puzzle."
Atlanta also announced right-handed reliever Jason Frasor was placed on the 15-day disabled list with a right shoulder strain. Frasor has allowed zero earned runs in six games since being signed July 16.
"I've never had a shoulder issue in my life, literally," Frasor said Tuesday. "I'm an elbow guy. Three elbow surgeries, a couple Tommy Johns. But I pitched Saturday night in Philly -- everything was fine.
"And Sunday I got up going to the game and couldn't do it. There was just something back there. I get a cortisone shot tomorrow, calm it down and figure out a way to get through the next two months. ... I'm not shutting it down; I want to finish pitching the year for the Braves."
First baseman/outfielder Joey Terdoslavich and right-hander Ryan Kelly were both recalled from Triple-A Gwinnett.
Carlos Collazo is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.