The Pirates optioned Murdock to Triple-A Indianapolis prior to Sunday's 14-5 win over the Brewers.
Murdock was up with the Pirates as their 27th man for Saturday's doubleheader, but he went unused in both ends of the twin bill. The 27-year-old righty is still waiting to make his Pittsburgh debut after he signed a minor-league deal with the organization in the offseason before being added to the 40-man roster July 5.