The Astros optioned Kuhnel to Triple-A Sugar Land on Sunday, Matt Kawahara of the Houston Chronicle reports.
Houston will swap Kuhnel out of its bullpen for Parker Mushinski, who was called up from Sugar Land in a corresponding move. After being acquired from the Reds on June 17 before receiving a call-up July 8, Kuhnel gave up four earned runs over two innings in his first two appearances with the Astros.