Colon has two wins against a league-leading seven losses and a 7.78 ERA. In his last start Monday against the Phillies, Colon surrendered eight earned runs in 3 2/3 innings.
Following the game, Colon said, "Physically and mentally I still feel good."
Braves manager Brian Snitker told a different story while discussing the move. Snitker said Colon has received treatment "for a while" for the oblique problem. He said he doesn't believe the injury is serious.
"I don't think it's a huge issue, but I kind of feel like there's something going on that's not allowing him to perform the way he's capable," Snitker said. "We just figured it's good to back off the stress and try to get him right. Hopefully everything clears up to where he can start doing what he's capable of doing."
Snitker said this was a time "you have to make a decision to protect a player from himself." He described Colon and other veterans as "warriors" who "have little things going on and they don't want to back off."
Colon signed a one-year, $12.5 million contract with Atlanta this offseason. He was coming off a solid season with the Mets in which he went 15-8 with a 3.43 ERA.
Colon is a four-time All-Star who won the Cy Young in 2005 with Cleveland. He's also pitched for the Angels, A's, White Sox, Red Sox, Expos and Yankees.
Information from The Associated Press contributed to this report.