They dont even have a contingency plan for a backup, it's not like Luck never missed a game.
Now they are going into the season with Scott Tolzien and even if Luck comes back by week 6 chances are they will be already doomed by then. Thats why the whole JimmyG saga has been a bit overplayed imho, it's not like BB has any obligation to trade him. Thats a plus when you already have a replacement, getting something in return. JimmyG replacement is not ready yet and backup QB is an important position. Sometimes its just simple as that.