Frias was recalled from Triple-A Reno by the Diamonbacks on Friday.
As a result of Cole Sulser (shoulder) hitting the 15-day injured list, Frias will make what figures to be a temporary return to the majors. The 24-year-old righty allowed 20 earned runs over 17 innings with the D-backs last season and will likely be used in low-leverage situations out of the bullpen.