The Reds optioned Zulueta to Triple-A Louisville on Saturday.
The move makes room on the 26-man roster for the reinstatement of right-hander Emilio Pagan (lat) from the 60-day injured list. Zulueta made five major-league outings since being recalled from Louisville on July 30, posting a 4.05 ERA and 1.50 WHIP across 6.2 innings. Across 29 outings in Triple-A this season, Zulueta has recorded two saves with a 2.18 ERA and 1.41 WHIP over 41.1 innings.