The Pirates traded Contreras to the Angels on Thursday in exchange for cash considerations, Alex Stumpf of MLB.com reports.
Contreras was designated for assignment by Pittsburgh on Saturday after posting a 4.41 ERA and 1.65 WHIP across 16.1 innings. The 24-year-old right-hander will replace Davis Daniel in the Angels' bullpen, though Contreras could also be moved into the starting rotation at some point.