Osuna was called up to the majors to serve as the 26th man for Wednesday's doubleheader against the Tigers, Rob Biertempfel of The Athletic Pittsburgh reports.
Osuna made his major-league debut for the Pirates last season, hitting .233/.269/.428 in 227 plate appearances. He's on a tear to start the season for Triple-A Indianapolis, hitting .333/.404/.533 through his first 13 games. Osuna will not be available for Game 1 of the doubleheader, but will start in right field during Game 2.