3 major USC football questions sure to keep Lincoln Riley up at night this summer

The USC Trojans overachieved in 2022 and underachieved in 2023. Where will they land on the spectrum in the 2024 college football season?

The possibilities are truly endless because Lincoln Riley and company have so much uncertainty coming into the season replacing a game-winning quarterback and a game-losing defensive coordinator.

The head coach will want to have complete faith in the coaching staff and roster he's put together but doubt is sure to creep in at some point. What are his biggest worries?

3. Can Miller Moss be the next great Lincoln Riley quarterback?

Caleb Williams was the 2022 Heisman Trophy winner and No. 1 overall pick in the 2024 NFL Draft for a reason. He is an astounding talent whose performance at USC arguably makes him the best signal to wear cardinal and gold.

Miller Moss will do his best to fill Williams shoes, unless UNLV transfer Jayden Maiava makes a serious surge to the top of the depth chart during Fall Camp.

Riley's offense has always been operated at a high level by a quality quarterback. Having the right guy behind center matters and this is the first time in a long time that the replacement for one of Riley's Heisman winners wasn't a sure thing.

Does Moss have what it takes to keep Riley's QB hit rate going?

We already know Moss can run Riley's system. We all saw it in the Holiday Bowl against a solid Louisville defense. He threw six touchdowns in the first look USC fans have gotten of him with the first team offense.

One performance doesn't prove a quarterback is capable of keeping his head game-in-game-out, play-in-play-out. And as fun as the Holiday Bowl was, it was an ultimately meaningless game. Taking on LSU, Penn State and Notre Dame is a whole other ask. Riley can't know for sure Miller is ready to go into the Big House and get a win until he makes that trip.

2. Can D'Anton Lynn do to USC's defense what he did to UCLA?

In 2022, UCLA's defense ranked 79th in FPI, two spots ahead of USC at No. 82.

In 2023, UCLA's defense ranked fifth in FPI, 85 spots ahead of USC at No. 90.

What changed for UCLA? They hired D'Anton Lynn. USC is hoping the same level of improvement is coming their way after poaching the defensive coordinator from their rivals.

It's safe to expect the Trojans to improve considerably on defense. Realistically, the difference between 8-4 and 10-2 could be the degree to which that defense improves.

Right now, Riley has to be crossing his fingers, closing his eyes tight and praying for a top 10 defense. If Lynn could do it once, he could do it again...right?

Circumstances are different, which is where the worry comes in. Lynn inherited Laiatu Latu, a Top 15 draft pick who had 13 sacks in 2023. USC doesn't have a comparable force off the edge, at least not one that's already proven. Depth on the defensive line is paper thin, even if there are players with huge potential like Bear Alexander, Anthony Lucas, Elijah Hughes and Braylan Shelby.

Lynn has his work cut out for him transforming USC's defense and Riley won't know for sure if he's got it right until Brian Kelly's LSU has a go at them.

1. Is USC's talent and depth in the trenches good enough for the Big Ten?

The Pac-12 was traditionally more of a finesse league. The offenses were high-flying. Speed was king. Now that USC is in the Big Ten, finding the balance between speed and size is the biggest challenge.

Offensive and defensive lines are just bigger in the Big Ten. So it doesn't help that USC's biggest concerns, by far, going into the 2024 season live on the offensive and defensive lines.

The Trojans have the pieces for a solid offensive line anchored by Jonah Monheim, who Pro Football Focus named the No. 3 tackle returning in 2024 (though he'll be at center this season). Will solid be enough when it comes to containing Michigan's Josaiah Stewart or Penn State's Abdul Carter, PFF's No. 9 and 10 returning edge defenders? Will they be able to stand up to top 10 interior linemen like Michigan's Mason Graham and Kenneth Grant or Notre Dame's Howard Cross III and Rylie Mills?

Even if the answer is yes, Riley needs an absurd amount of luck to make it through the 2024 season without any major injury issues on the offensive line because USC doesn't have a viable two-deep.

The defensive line is an even bigger concern. There's practically no quality depth and there's a dearth of 300-pound bodies capable of clogging up the middle. Realistically, USC needed a full transfer portal rebuild. They've only added Vanderbilt's Nate Clifton and Wyoming's Gavin Meyer.

If football truly is won and lost in the trenches (and it usually is), then Riley will be tossing and turning all summer wondering if his lines will give him more nightmares than USC's opponents.