The two linemen will replace injured players.
Aaron Smith replaces New York Jets defensive end John Abraham (knee) and Marvel Smith replaces Kansas City Chiefs offensive tackle Willie Roaf (ankle).
The addition of the two Smiths gives the Steelers eight players in the Pro Bowl, scheduled Feb. 13 at Aloha Stadium in Honolulu.
The Steelers were defeated 41-27 by the New England Patriots Sunday in the AFC championship game.
Aaron Smith led the team this season with eight sacks.