Urbik, who played all but seven snaps in Sunday's loss, will likely be a game-time decision, according to coach Doug Marrone. If he cannot play, J.J. Unga will start in his place at right guard.
Smith, who has been inactive for the past five games, was injured in Wednesday's practice.
Linebacker Kiko Alonso (knee) participated at the start of Thursday's practice. He showed a noticeable limp during positional drills after being limited in Wednesday's session.