"He pitched good against them last year here," Phillies manager Charlie Manuel said. "And he's on his regular day."
Happ, who threw a shutout Saturday against the Blue Jays, faced the Braves twice last season. He threw six scoreless innings against the Braves at Turner Field on Sept. 17 and allowed two runs in 6 2/3 innings against the Braves at Citizens Bank Park on Sept. 22.
The Phillies now need a pitcher to start Friday.
It is believed right-handers Andrew Carpenter and Carlos Carrasco are the favorites for that spot, with right-handers Kyle Kendrick and Rodrigo Lopez also candidates.
"We've got some options for Friday," Manuel said. "We don't know what we'll do yet."
Todd Zolecki is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.