The redshirt sophomore replaced Brandon Wimbush in the starting lineup, two days after coach Brian Kelly sidestepped questions about making a change at the position.
The Fighting Irish (3-0) won their first three games by a total of 20 points and didn’t score more than 24 points in any of those games.
Notre Dame scored on its first possession in each of its first three games this season under Wimbush — with two touchdowns and a field goal — but failed to score on the first drive Saturday with Book.
Book led Notre Dame to a 33-10 rout of North Carolina last year when Wimbush was injured and led a second-half rally in a Citrus Bowl victory over LSU. His only previous action this season came last week against Vanderbilt, completing all three passes for 13 yards and a touchdown.
ESPN Stats & Information and The Associated Press contributed to this report.