CHARLOTTE, N.C. -- Florida State started true freshman Brock Glenn in Saturday night's ACC championship game against Louisville in place of Tate Rodemaker, who sustained a concussion last weekend and was ruled out.

Rodemaker was in pads and warmed up pregame, but was ultimately deemed unavailable for the clash. AJ Duffy backed up Glenn against the Cardinals.

Glenn, a former four-star recruit out of Lausanne Collegiate School in Memphis, Tennessee, had thrown just four career passes at Florida State entering the game, including an incompletion against Florida while Rodemaker was being tested for a concussion last week.

Glenn took all live reps in practice this week.

"When you see Brock and his skill set that he brings even through the week of practice," coach Mike Norvell said Friday, "we're all preparing to play, and it's the same thing we faced a week ago. He knew he was going to be one play away and ultimately he had to go in and be ready for that situation, and he was. We've approached it the same way."

Rodemaker sustained the concussion on a late hit in the fourth quarter of the Seminoles' Week 13 win over Florida. Gators defender Jaydon Hill was ejected for targeting after the play, and Rodemaker retreated to the injury tent for evaluation. He returned two plays later to help cap a touchdown drive.

Norvell said Rodemaker did not have concussion symptoms during the game, but on Sunday was added to the protocol.

Rodemaker made just his second career start against Florida after FSU lost incumbent Jordan Travis to an ankle injury the previous week. Glenn becomes the third different quarterback to start for the Seminoles in as many weeks.

Norvell insisted Friday the game plan would not change dramatically, and he said Glenn brings ample talent and confidence to the role.

"He's still young, but he's mature beyond his age," Norvell said. "When you step around someone and they have [confidence], and it's real, it gives everybody around them confidence as well. He's not going to hold back. He's going to put all he has into it. ... I've got a lot of confidence in what that's going to look like."

The last quarterback to make his first career start in a Power 5 conference title game was Ohio State's Cardale Jones, who led the Buckeyes to a 59-0 win over Wisconsin in the 2014 Big Ten finale, then proceeded to beat Alabama and Oregon en route to a national championship.