Bulger left late in the first quarter with a bruised right shoulder after a sack by Aaron Kampman. Bulger fumbled on the play at the St. Louis 15, setting up a Packers field goal.
Bulger was 3 for 4 for 23 yards before being replaced by Kyle Boller.
Robinson suffered an ankle injury on St. Louis' final drive of the first half. Robinson, the Rams' leading receiver this season, had two catches for 26 yards.
Butler hurt a knee early in the first quarter.
The extent of the injuries was not immediately known.