McCann had surgery to repair a torn labrum in his right shoulder last October. He was expected to complete his rehab assignment with Triple-A Gwinnett on Sunday and accompany the team to Cincinnati.
Rookie catcher Evan Gattis has hit .250 with seven homers and 17 RBIs. Gattis, the NL rookie of the month for April, is expected to play behind McCann and may have spot starts at first base and in the outfield.
Gonzalez says third baseman Juan Francisco is day to day with a mild right ankle sprain he suffered Friday.
Right fielder Jason Heyward, who had his appendix removed on April 22, is ready to take batting practice.