Brian Hoyer suffered a broken arm in the second quarter of the Chicago Bears' 26-10 loss at the Packers.
Hoyer was hit hard by Green Bay defenders Julius Peppers and Clay Matthews on a third-down pass attempt that fell incomplete with 10:03 left in the quarter.
Hoyer has been starting in place of Jay Cutler, who is nursing a thumb injury.
Matt Barkley finished the game for the Bears.