The Pirates selected Heller's contract from Triple-A Indianapolis on Thursday, Noah Hiles of the Pittsburgh Post-Gazette reports.
Heller has been torched for 12 runs (11 earned) over just two innings in two appearances with the Pirates this season. He's put up great numbers this season at Indianapolis, however, with a 3.55 ERA and 55:13 K:BB in 33 frames. He'll get another chance with Pittsburgh in a middle-relief role.