The Braves waited until after batting practice to clear a roster spot for left-hander Chuck James to be recalled from Triple-A Richmond to start against Milwaukee on Friday night.
McCann took batting practice and caught in the bullpen on Friday before he was cleared by the team's medical staff. He said he will be available to pinch-hit until Monday, when he plans to start.
Rookie catcher Clint Sammons, who had three hits, including his first career homer, and drove in three runs in Thursday night's win over St. Louis, was in the starting lineup again on Friday night.
"He caught a nice game as well," said manager Bobby Cox.
Sammons appears set to remain on the roster as the backup when McCann starts.
Miller was only 5 for 54 with one homer and three RBIs. He started 15 games.
McCann left Sunday's game with a mild concussion sustained in a collision with Philadelphia's Shane Victorino.
"I'm able to pinch-hit the next three nights and catch in an emergency," McCann said after batting practice. "On Monday I'll be back in there every day."
McCann, an All-Star, is hitting .302 and leads all major league catchers with 20 homers, 28 doubles and 63 RBIs.
Cox is eager to have McCann bolster the depleted middle of the Braves' lineup.
"He feels as good as he can feel," Cox said.
All-Star third baseman Chipper Jones has been on the disabled list since July 24 with a hamstring injury. First baseman and cleanup hitter Mark Teixeira was traded to the Los Angeles Angels on Tuesday.
Tim Hudson, facing probable season-ending elbow surgery, plans to test the elbow one more time this weekend even though he acknowledges an MRI exam has shown significant damage.
Hudson didn't throw on Friday but said he won't wait long to try to throw on the side.
"It will probably be tomorrow, that's my guess," Hudson said.
At least two doctors have determined Hudson needs Tommy John ligament replacement surgery. The normal recovery period from the procedure could force Hudson, the team's ace, to miss the rest of the season and at least the first half of next season.