The Pirates also announced they have released pitchers Jeff Robinson (3-1, 4.46 earned-run average) and Jerry Don Gleaton (1-0, 4.26).
Pittsburgh purchased contracts of three minor league pitchers to fill the roster spots: Paul Wagner from double-A Carolina and Steve Cooke and Blas Minor, both from triple-A Buffalo.
Wagner will make his major league debut today, replacing Smith in the rotation against the Braves.
Mike Roesler, a pitcher for the Buffalo Bisons--the Pirates' triple-A affiliate--was released the day after he made an obscene gesture and cursed at fans during a game.
Roesler cursed and gestured at fans behind the Buffalo dugout when he was removed from the second game of a doubleheader against the Oklahoma 89ers on Friday night.
Roesler, who was 3-5 this season, gave up three runs in one-third of an inning during Buffalo's 12-2 loss.