No. 3 Notre Dame looks to keep its undefeated season and College Football Playoff hopes alive this weekend against Florida State, and it sounds like it will have to do so without starting quarterback Ian Book. Multiple outlets are reporting that Book suffered a rib injury during Notre Dame's 31-21 win over Northwestern and that the injury will likely keep him sidelined this weekend.

It's not clear when Book was injured against Northwestern, but he did take a big hit early in the first quarter and was slow to get up afterward. He played the entire game, however, throwing for 343 yards and two touchdowns, and he also put the game away with a fourth-quarter touchdown run.

The good news for Notre Dame is that the first three of its nine wins this season came without Book as its starting QB. Brandon Wimbush opened the season as the starter and will return to the role this weekend if Book can't go.

Still, since Book took over for Wimbush as the starter, the Notre Dame offense has gone to a new level. The Irish scored an average of 23.3 points per game in Wimbush's three starts but have scored 38.8 points per game in Book's six starts. That's a difference of over two touchdowns per game.