Ian Book’s accuracy is a big reason Notre Dame is No. 3 in the College Football Playoff rankings. The redshirt sophomore is completing 74.5 percent of his passes, sparking an offense that has scored at least 31 points in five of his six starts since he took over for Brandon Wimbush.
If the Irish (9-0) want to remain on the playoff path, they might have to get it done this week without Book. Coach Brian Kelly said Thursday that Book is “day to day” for Saturday night’s game against Florida State (4-5) because of an “upper-body” injury.
“(Book has) been at practice, but he’s been limited,” Kelly said.
Kelly said Wimbush has received the bulk of the work this week, “but we’ll see what happens Saturday.”
Book suffered the injury — reported as a rib injury earlier Thursday by multiple media outlets — during last week’s win at Northwestern.
The potential setback could be a big blow for a team pursuing its first CFP berth. Book replaced Wimbush as the starter in Week 4 at Wake Forest, and Notre Dame’s offense has flourished.
Book has passed for 1,824 yards with 15 touchdowns and four interceptions.
“We knew he was banged up during the game and (knew) in subsequent follow-ups on Sunday that we were going to have to keep an eye on him throughout the week,” Kelly said.
Wimbush is an experienced option if Book is unavailable.
“It’s awesome to have a guy like that that our players really respect and are excited if he has the opportunity to play,” Kelly said. “They’ll rally around him.
“He doesn’t have to come in, if he has to play, and go win the football game. We’ve got some other pretty good pieces. We’ve got a pretty good defense. And if he’s called upon, he’ll do a great job. He’s prepared himself.”
Wimbush started 12 of 13 games last season and fought off Book to earn the starting role at the beginning of the season. He led the Irish to a 24-17 victory against Michigan in the opener, passing for 170 yards with one touchdown and one interception and rushing for 59 yards.
“The quarterback that is taking reps for us is a guy that you would say is of championship quality,” Kelly said. “He’s 12-3 (as a starter) for a reason.”
But Wimbush struggled in his next two starts, throwing three interceptions against Ball State and completing 13 of 23 passes for 122 yards against Vanderbilt.
Overall, Wimbush has appeared in four games this season, completing 55.3 percent of his passes for 589 yards with one touchdown and four interceptions. He also has rushed for 144 yards and a touchdown on 52 carries.
“He just needed to make a couple of fine-tune mechanical things,” Kelly said. “He’s thrown the ball pretty good this week.”
Freshman Phil Jurkovec also received reps in practice this week.
“If Phil has to play, we can win,” Kelly said.
Earlier this week, Kelly praised Wimbush for the way he has handled the demotion. He also reminded Wimbush that he needed to remain prepared.
“He knows that he’s one step away from going back out on the field,” Kelly said Tuesday.
That opportunity could come Saturday.