Frias was recalled from Triple-A Reno on Saturday.
Frias was promoted from Double-A Amarillo to Triple-A Reno on Aug. 16. Since, he's posted a 5.82 ERA and 1.75 WHIP while walking 16 hitters across 21.1 frames and five starts with Reno. While it's unclear when Frias will first take a major-league mound, it's likely that he'll draw a start in the coming days.