Warren's contract was selected by the Angels on Wednesday, Rhett Bollinger of MLB.com reports.
Warren has made 22 appearances (one start) at Triple-A Salt Lake this year, and he's accumulated nine innings across his last three outings. The right-hander's 6.19 ERA this year has been skewed by several rough outings, but he's posted a 2.70 ERA and 0.90 WHIP in 13.1 innings across his last six appearances. He'll now be in line to make his major-league debut, likely out of the Angels' bullpen.