COLUMBUS, Ohio (AP) — More than ever this season, the backup quarterback spot has become the most important position in the Big Ten.

Half of the conference's 18 teams could have their second-string QB under center this weekend. That includes second-ranked Ohio State and No. 7 UCLA, who are dealing with injuries.

Michigan and Rutgers, who meet on Saturday, could also be a battle of backups. The other teams wrestling with QB decisions are Illinois, Iowa, Michigan State, Oregon and Washington.

While most of the changes have been because of injuries, Ohio State coach Ryan Day didn't have any answers for the attrition in the conference this season.

Day does know, though, that the changes in roster construction because of the transfer portal and NIL have made it difficult to build a solid QB room.

“It’s more of a challenge than ever to keep and retain a lot of quarterbacks in your room because a lot of these guys want to play. And so our ability to get these young guys ready to go on the field and play is going to be critical and it’s a huge challenge for everybody in the program,” Day said. “But over are the days when you stack guys and developing them along the way.”

Ohio State will start either Luke Fahey or Tavien St. Clair for Saturday's prime-time contest at Southern California. Fahey came in during the fourth quarter of the 19-15 victory over Indiana on Oct. 17 after Julian Sayin hurt his throwing arm.

“We need to stack a few more days and then we’ll kind of go into the game and figure out what gives us the best chance to win,” Day said. “We’ve got to be smart about preparation and every rep. The good news was we did have some snaps last week that were extra (because of the bye week), so that was good.”

Fahey, who had the edge the past couple weeks according to Day, played 10 snaps against the Hoosiers and went 0 for 2. The freshman has played three games this season and is 9 of 13 for 203 yards with two touchdowns and two interceptions.

St. Clair, a sophomore, has played two games and is 5 of 7 for 52 yards with one touchdown and one interception.

Sayin is sidelined indefinitely, but Day has not said if he could miss the rest of the season.

Senior Ty Dieffenbach is expected to be UCLA's starter for the rest of the season after Nico Iamaleava suffered a knee injury at Oregon on Oct. 10.

“I think a lot like our team, he’s got resolve, he sticks together, he has confidence in himself and he’s excited to go make plays, not nervous to make mistakes," coach Bob Chesney said.

Dieffenbach has a 61.4% completion rate with two touchdowns and an interception. The advantage he has is a running game that is averaging a conference-high 233 yards per game with Wayne Knight and Anthony Woods both averaging at least 65 yards per game.

The Bruins host Nevada on Saturday but have a favorable slate until they head to Michigan on Nov. 21 and host USC one week later.

The one team that seemed to stack quarterbacks was Oregon, who came into the season with Dante Moore as the starter, Nebraska transfer Dylan Raiola as the primary backup and Brock Thomas also adding depth.

Oregon's season turned, though, when Moore suffered a season-ending concussion at USC on Sept. 26. The Ducks haven’t scored more than 17 points in their last three games.

Raiola came in and passed for 289 yards and two touchdowns against the Trojans, but has dropped both of his starts. Thomas started against Nebraska, but was pulled after completing less than half his passes.

Coach Dan Lanning fired offensive coordinator Drew Mehringer on Sunday after losses in two of the last three games. Whether new play caller Jay Johnson can do anything to revive the offense will be seen with tough tests upcoming against No. 20 Northwestern on Saturday and Ohio State next week.

Illinois' Michael Clayton II is the only true freshman QB to start and win a game in the conference this season after he passed for 88 yards and a touchdown in last week's 21-10 win over Oregon. Katin Houser is expected to miss the next three to five weeks as he recovers from surgery on his throwing hand.

Washington's Desmond Williams could be back after missing the Oct. 16 game at Purdue, but coach Jed Fisch said he would not announce if Williams or Elijah Brown would start. Brown passed for a career high 302 yards against the Boilermakers.

Michigan State is on their bye week after starting third-stringer Kayd Coffman at UCLA. Coach Pat Fitzgerald hopes to have either starter Alessio Milivojevic or Cam Fancher back for the Nov. 7 game at Michigan.

The Hawkeyes have listed their starting QB as Hank Brown or Jeremy Hecklinski on the depth chart for Saturday's game against No. 25 Wisconsin.

Both struggled last week in a loss at Minnesota. Hecklinski was 9 of 16 for 62 yards and an interception in the red zone. Brown played the second half and went 11 of 21 for 136 yards.

Then there is Michigan at Rutgers, where neither coach is tipping their hand.

The Wolverines could go back to Bryce Underwood or give Tommy Carr another opportunity. Michigan has the second-worst offense among Power Four programs and is No. 127 in the Football Bowl Subdivision in passing offense.

“That’s to be determined,” Michigan coach Kyle Whittingham said about his quarterback. “I don’t want to play this game every week. Who’s going to start? That will be a decision we’ll make in the next couple of days here. Again, keep it to ourselves until somebody lets the cat out of the bag.”

Rutgers might give AJ Surace his second start after Dylan Lonergan was injured last week at Northwestern.

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