The Braves are being cautious with McCann, who has been sidelined since July 26. The 27-year-old catcher was hoping to be activated Friday, but it now appears he'll have to wait until at least Sunday.
"What's the difference between him being out 15 or 18 days in the grand scheme of things?" Braves manager Fredi Gonzalez said.
McCann experienced no problems when he blocked balls in the dirt and completed some other catching-related activities early Tuesday afternoon at Sun Life Stadium. But rain prevented him from taking swings outdoors for a second straight day.
After McCann works out again Wednesday, the Braves will likely have a better idea about what he will be doing this weekend. He will more than likely need to play at least two rehab games before being activated.