The Pirates recalled Brannigan from Double-A Altoona on Thursday.
He'll grab the roster spot vacated by the injured Spencer Horwitz (hamstring). Brannigan got a late start to the season after fracturing his nose during spring training, and he's hit .235/.333/.522 with eight homers in 31 contests at Altoona since returning. The 25-year-old is likely set for a reserve role, and he'll be making his major-league debut when/if he gets into a game.