McCann took batting practice before Monday's game at Florida after taking light hitting and throwing on Sunday.
"It felt fine; it felt exactly how I thought it would," McCann said. "I didn't try to swing as hard as I could. But I was pleased with how the ball was coming off my bat.
"It's my first time really swinging more than 50 percent, so I didn't want to let it go. I felt really good swinging that bat as far as hitting the sweet spot and hitting line drives."
McCann suffered an oblique injury on July 26.
McCann said he hoped to play minor-league rehab games on Wednesday and Thursday before joining the Braves at Turner Field for the first game of a series against the Cubs on Friday.
Manager Fredi Gonzalez was a little less sure, telling O'Brien: "That scares me, sending him out for a rehab assignment behind the plate."
Going into Monday's game, David Ross has started nine games and played in two more since McCann's injury and has struggled as an everyday player, hitting .171/.216/.286 with one homer in 38 plate appearances. McCann is the Braves' top hitter, hitting .306/.375/.514 with 18 homers.For more baseball news, rumors and analysis, follow @cbssportsmlb on Twitter or subscribe to the RSS feed.