Hartlieb was recalled by the Pirates on Tuesday, Adam Berry of MLB.com reports.
Hartlieb began the season at the alternate training site, but he'll join the Pirates after Kyle Crick (shoulder) and Clay Holmes (forearm) were placed on the 10-day injured list Tuesday. However, the 29-year-old shouldn't play a prominent role in the bullpen after posting a 9.00 ERA and 2.00 WHIP over 35 innings in his first season in the majors last year.