UCLA football is off to a hot start in the Bob Chesney era, but the Bruins will have to continue their season without their quarterback.

Nico Iamaleava will not be playing for UCLA when it takes on Wisconsin on Saturday, Oct. 17. He is out for the rest of the season after suffering a leg injury in the win against Oregon.

It's an injury that drastically alters UCLA's trajectory. The Bruins are 5-0 and ranked No. 12 in the US LBM Coaches Poll, with a plausible path to the College Football Playoff. While that is still possible, things become uncertain when the starting quarterback is no longer in the mix.

Here's what to know about Iamaleava as the Bruins try to continue their perfect start.

What happened to Nico Iamaleava?

Iamaleava suffered a knee injury against Oregon on Saturday, Oct. 10. Late in the second quarter, he scrambled and was tackled by Bear Alexander and Jerry Mixon, and his left leg looked like it got hit and then get twisted.

The quarterback was attended to by medical staff and returned one play later, throwing an interception. When UCLA came back out after halftime, Iamaleava was not on the field and later came out with his uniform off.

It was reported on Monday, Oct. 12 Iamaleava suffered a season-ending injury. UCLA has yet to confirm its quarterback's status, but Chesney said there was "serious concern" for his status.

Is Nico Iamaleava out for the season?

Yes, Iamaleava is out for the rest of the season. Reports indicate it is a knee injury.

How Nico Iamaleava injury affects UCLA

It's a big blow as Iamaleava possess an elite arm and an ability to extend plays that has gotten his team out of bad situations several times over his two seasons at UCLA. His ability forces defenses to respect the passing attack and allows UCLA's excellent running game opportunities to break free for big runs, despite some uneven play from the QB.

Iamaleava has the potential to stand among the best quarterbacks in the country, but he has had some struggles in 2026. He finishes the year 72-for-116 with 982 yards with four touchdowns and four interceptions, as well as 144 rushing yards and one touchdown run.

Who is UCLA's backup quarterback?

UCLA has two options at backup quarterback: Ty Dieffenbach and Madden Iamaleava, Nico's younger brother.

Cal Poly transfer Dieffenbach came in relief in the win at Oregon, his first appearance for the Bruins. He played well in limited throws, going 3-for-6 with 43 yards and a touchdown.

Prior to that, Iamaleava was the backup for his older brother, mostly coming in when the eldest Iamaleava was injured and missed only a brief period of action.

Chesney said the backup spot was determined on a week-to-week basis and the same approach will be applied going forward for the starting role, although it appears Dieffenbach is slated to assume the role.

“It'll be one of those things that we'll just be able to get started with Ty here and see how the rest of this plays out,” Chesney said. “There's two guys that are very capable, and I think that's a positive to have.”