Notre Dame will have to rely on demoted quarterback Brandon Wimbush tonight to continue its unbeaten season.

As you probably know by now, starter Ian Book, who put new life in the Irish offense when he took over for Wimbush after the third game of the season, is sidelined with injuries reported to be to his ribs and midsection.

Head coach Brian Kelly said Book would be ready for the Syracuse game but practiced little this week. He said Wimbush took the majority of the snaps at practice.

With Wimbush now back at starter, the Irish are not facing a Florida State team with a green and inexperienced signal caller. Wimbush directed the Irish to three wins this year before being replaced, including the win over Michigan in the opener. Wimbush is 12-3 as a starter.

Of course, the negative on Wimbush is his passing game and decision making in key spots which led, in part, to Book taking over. Book is a better passer. Wimbush, however, has better speed and uses it to run the football.

Wimbush has taken his demotion like a team-player helping Book during practices and meeting with him before and after games. This is a big opportunity for Wimbush to show people he is a good quarterback that would be able to start for a lot of teams across the country.

Notre Dame’s defense led the way, again, to victory in the Irish’s 31-21 win over Northwestern. Although the Irish offense came to life in the second half, it was the defense that came up with the big plays to preserve the ninth victory for the Irish.

ND’s offense did come up with a key, 89-yard, 10-play drive in the final quarter to move ND up by 10 points, with 2:45 left. The drive was capped by Book’s 23-yard score. ND’s defense then took over and held the Wildcats in check forcing Northwestern to turn the ball over to the Irish in a four-and-out series.

Overall, the ND defense held its third opponent of the season under 250 yards (249), and in the process recorded five sacks, and held the Wildcats to five third-down conversions in 15 attempts and 3.6 yards per play average.

Book faced the highest-rated pass-efficiency defense so far this season and, after a slow start, finished with a career-high 343 passing yards. Book’s third quarter performance was the key as he completed 11 of 14 passes for 195 yards and two TDs.

For the day, Book was 22 of 34 passing with no interceptions for the 343 total yards and two TDs. Dexter Williams had 56 yards on 19 carries and a TD, Jafar Armstrong 18 on four and Book 56 on 11. Chase Claypool caught eight for 130 yards while Miles Boykin had 54 on four and a score and Chris Finke 45 on five. Michael Young picked up 60 yards on two catches and a score. Justin Yoon, returning from a groin injury, hit one field goal for 43 yards but missed a 44 yard attempt.

Defensively Te’von Coney had 10 tackles while Daelin Hayes had seven and Julian Love six. Coney also had two tackles for losses as did Hayes. For the game, ND had total yards of 464 to 249 for the Wildcats.

Tonight the Irish face a Florida State team that has been struggling all season. The Seminoles come into the game at 4-5 with wins over Samford, 36-26; Northern Illinois, 37-19; Wake Forest, 38-17; and Louisville, 28-24. The five losses have been to Virginia Tech, 24-3; Syracuse, 30-7; Miami, 28-27; Clemson, 59-10; and North Carolina State, 47-28. The Seminoles best performance was the Miami loss and the Clemson defeat was the worst for FSU in many years.

The Seminoles switched quarterbacks last week, giving the starting spot to James Blackman. Deondre Francois has been the starter most of the season. Press reports indicate Francois will be back as starter tonight.

The rushing attack is led by Cam Akers who has 467 yards on 112 carries and three TDs. The top receiver is Nyqwan Murray with 40 catches and 536 yards and three TDs.

Florida State leads the series, 6-2-0, with the Irish losing the last three games against the Seminoles in 2003 (37-0), 2011 (18-14) and 2014 (31-27). The last Irish win was in 2002, 34-24.

The game will be televised nationally by NBC-TV with a 7:40 p.m. kickoff.

IRISH NOTES ... Tonight is senior night and all senior members of the squad will be honored with their parents prior to the start. ND has 12 players with expiring eligibility that will be among those honored tonight. They are offensive linemen Sam Mustipher and Alex Bars, running back Dexter Williams, defensive linemen Jonathan Bonner and Jerry Tillery, linebackers Drue Tranquill and Te’von Coney, tight end Nic Weishar, safeties Nick Coleman and Nicco Fertitta, and kickers Justin Yoon and Tyler Newsome. Also, there are eight seniors with fifth-year options, some of whom will be back and some who won’t. They are quarterback Brandon Wimbush, wide receivers Mikes Boykin and Chris Finke, tight end Alizé Mack, offensive lineman Trevor Ruhland, defensive lineman Micah Dew-Treadway, rover Asmar Bilal and cornerback Shaun Crawford ... It will be a cold night in South Bend with game time temperatures only in the mid to lower 30s and a chance of snow showers or flurries ... Sophomore Jordan Genmark Heath started last week in place of ND’s second-leading tackler, Drue Tranquill, who suffered a high ankle sprain against Navy. Tranquill played in a limited role and made five tackles. Tranquill will start tonight ... Florida State has not suffered a losing college football season since 1976 but it could happen this year ... ND moved up to number three in the NCAA playoff standings thanks to LSU losing to No. 1 Alabama ... Book ranks first among all quarterbacks in the FBS this season with a 74.5 completion percentage over his seven games played ... Yoon is just six field goals shy of breaking the Notre Dame career field goals record held by Kyle Brindza. Yoon has connected on 52 career field goals entering Saturday’s game ... TE Alize Mack, who missed last week’s game due to a concussion, will play tonight ... Notre Dame has not had an empty seat for a home game since 1973. The sellout streak reaches 268 consecutive games tonight ... ND is a 16 point favorite tonight ... In my preseason picks I have the Irish winning tonight. With Book out and Wimbush in there is a bit of uncertainty tonight. Wimbush does come in with a lot of game experience. As long as he protects the football, ND should prevail.