Borucki (wrist) will start his rehab assignment with Triple-A Indianapolis on Saturday.
Borucki, who has been on the injured list since early April due to carpal tunnel syndrome in his left wrist, was shut down from his throwing program at the beginning of August after suffering a setback. He appears to have recovered enough to return to a live setting, and the hope for the 30-year-old is that he'll be available out of Pittsburgh's bullpen for the tail end of the regular season.