The Pirates optioned Murdock to Triple-A Indianapolis on Friday.
After making just one appearance with Pittsburgh since being recalled Tuesday, Murdock will head back to the Triple-A squad. With Indianapolis, the 28-year-old has posted a 0-2 record, 4.21 ERA, 1.13 WHIP and 36:11 K:BB over 25.2 innings this season. Pittsburgh recalled Evan Sisk to replace Murdock on the 26-man roster.