The Pirates selected Curtis' contract from Triple-A Indianapolis on Saturday, Alex Stumpf of MLB.com reports.
Curtis will join the major-league roster to give Pittsburgh some extra pitching depth for Saturday's twin bill against the Guardians. The 24-year-old righty has turned in a 5.57 ERA and 1.67 WHIP across 21 innings since being promoted to Triple-A in June and will presumably fill a multi-inning role out of the bullpen to begin his MLB career. Oneil Cruz (hand) was transferred to the 60-day IL in a corresponding move.