The Pirates transferred Contreras from Single-A Bradenton to Triple-A Indianapolis on Tuesday, Justice delos Santos of MLB.com reports.
After accumulating a 6.59 ERA and 1.57 WHIP through 68.1 innings in the majors, the Pirates optioned Contreras all the way down to the Florida Complex League so he could work on his mechanics. After a two-inning appearance with Bradenton on Friday, Contreras will now face higher-level competition and could return to Pittsburgh later this season if he performs well in Triple-A.