The Diamondbacks recalled Frias from Triple-A Reno ahead of Sunday's game against the Cardinals.
Frias will give Arizona some much-needed length out of the bullpen in the series finale after five relievers were needed to cover the final 3.2 innings of Saturday's 16-7 loss to St. Louis. One of those relievers, Edwin Uceta, was optioned to Triple-A to clear a spot on the 26-man active roster and in the bullpen for Frias, who is expected to work in a low-leverage role for the duration of his stay in Arizona.