Sims was optioned back to Triple-A Gwinnett on Sunday, David O'Brien of The Atlanta Journal-Constitution reports.
Sims got the call Saturday and appeared for the second time this season, giving up two earned runs on three hits and a walk across 3.2 innings, striking out six along the way. Despite allowing a pair of runs, he was much more effective than his first appearance back on April 19, when he gave up three earned runs and three walks while just recording one out. His time in the majors will once again be short-lived, however, as Sims will return to Gwinnett in favor of fellow right-hander Luke Jackson.