Cunniff has been optioned to Triple-A Gwinnett, Mark Bowman of MLB.com reports.
Since being called up by the Braves on August 3, Cunniff has only pitched 3.2 innings for the Braves, giving up three runs and walking four. The 27-year-old will head back to Triple-A Gwinnett where he has a 4.66 ERA in 36.2 relief innings.