The Pirates reinstated Holderman (illness) from the 15-day injured list Thursday.
Holderman appeared in four games during his rehab assignment at Triple-A Indianapolis. He gave up three earned runs in just two-thirds of an inning during his first game but did not allow another run to score in his final three. He'll likely reprise his role as a high-leverage reliever in Pittsburgh's bullpen, though opportunities for saves will be minimal with David Bednar and Aroldis Chapman healthy.