In a rule established in the most recent Collective Bargaining Agreement, clubs can carry 26 players for designated regular or split doubleheaders that occur at least two days after the originally scheduled game was postponed.
Rosenberg pitched in two games in a recent brief stint with the Phillies. The right-hander made his Major League debut on June 9, when he allowed two runs in one inning in a loss. He also allowed two runs in his other outing on June 12, when he pitched two-thirds of an inning.
Rosenberg's promotion gives the Phillies a fourth right-handed relief option out of the bullpen for Sunday.
Jake Kaplan is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.