Heredia was optioned to Triple-A Gwinnett on Sunday.
The 31-year-old has appeared in only four games with seven plate appearances since the All-Star break, and he'll head to Triple-A to make room on the big-league roster for catcher Chadwick Tromp. Heredia has a .549 OPS in 47 games this year and could rejoin Atlanta down the stretch if the team needs outfield depth.