While it seems like it just started, USC is technically winding down fall camp this week. Next will come a mock game week, as the Trojans transition to the schedule and routine they'll keep in-season, and then it's Week 0 leading into the opener vs. San Jose State.

So especially now, every rep matters and every practice is an audition as the Trojans maintain several key unsettled positions.

Or many, according to head coach Lincoln Riley.

"Tightest position battles ...," Riley said Tuesday, taking a pause to consider the question. "Man, I think running back. I would say every receiver position. I would say defensive line reps. We know some guys are going to play. but is it going to be a third, is it going to be a half, are you going to be a starter, going to be a 2, going to be a 3? Inside linebacker, for sure, free safety, both corner positions. I mean, a lot. A lot. That’s a lot more than – if I would have answered this question truthfully last year at this time, there wouldn’t have been quite that many."

One of the major storylines this year for the Trojans is the significantly improved depth across the board -- not just depth but an influx of talent disrupting the status quo.

"In a very healthy way," as Riley put it.

RELATED: Full video and transcript of Lincoln Riley's comments Tuesday | Video interviews with USC defensive coaches and players | Photo gallery from Tuesday's practice

"There’s guys, you can make a case for them being a starter and you can make a case for them being a 3," he said. "Again, some of the areas are deep and that’s good. I think it’s going to allow us to withstand all that comes at you through the season, withstand injuries as they come up, be able to get personnel on to take advantage of certain matchups, whether it’s any side of the ball.

"But yeah, our guys feel the sense of urgency. To give you an example, there’s a number of guys on this roster that played significant snaps right now that feel an incredible sense of urgency of, I gotta go, like now, and that’s good. That’s the only way you get better at something. So i think our guys have responded well to it, I don’t think it’s been taken as a negative, but you can feel the pressure there, for sure."

The message is overt -- just because a player may have been a starter or key rotation piece on an 11-win USC team last year, that doesn't guarantee anything this fall. Just because someone may have been a buzz-worthy transfer addition, that doesn't cement a spot on the depth chart.

Maybe this isn't yet the peak roster Riley and Co. envision in building a national championship contender, but it's getting closer and it's come quite a ways from last year when the Trojans essentially had one cornerback they fully trusted and several they were developing, had such limited depth at linebacker that when two starters were out they had to move defensive lineman Tuli Tuipulotu out of position and adopt a dime package to fill the void with an extra defensive back.

Defensive tackle Stanley Ta'ufo'ou logged more than 500 snaps on defense last year and would seem to now be at best in a much-reduced time share with transfer reinforcements Bear Alexander and Kyon Barrs making their case for those interior defensive line spots.

The RUSH position that was so thin last year, the Trojans never really found the production they were seeking there while ultimately moving defensive end Nick Figueroa over there to provide some baseline stability at least. Now, there are legitimately a handful of pass rushers vying for the role, all with significant intrigue and a chance to contribute.

For that matter, there are too many safeties/nickels with a strong case for playing time than there is playing time to give.

And that's not even getting into the familiar logjam at wide receiver and running back.

"There are more positions where you look at it like, man, I could see this going several different directions. Just a healthier, more talented roster overall – and using the word healthy in terms of having a lot of competition and that competitive depth that we’ve talked about all offseason. You see that," Riley said. "Whether it’s guys that were here on our team last year or whether it’s newcomers, what it took to get on the field in certain positions, it’s a little bit different definition this time around.

"There’s no assumptions on what guys did at a different school or what guys did here or anywhere else. We really tried to stress that with the guys, it’s based on what we’re seeing on this field right now. Lot of battles and a lot of good players on the field that we’re excited about. Obviously, this is going to move quick into mock game week. This will be a big stretch. We’ll practice here the next couple days and really kind of conclude our camp with a scrimmage here this Saturday."

So the competitions continue now nine or so practices into camp with time running out before decisions for Week 1 will have to be made -- though, as this staff showed last year, it will continue the evaluations all through the fall and won't hesitate to make changes on the fly.

But at least preliminarily, some of those spots could be crystallizing over the next week.

"This is a big week for our guys. A lot of the reps you’re going to start putting into the different groups, offensively, defensively, special teams are going to start to narrow here toward the end of this week," he said. "So for guys who want to stake their claim for why they want to be on the field, this is go time. This is it."

With that, let's dive deeper into the position battles that remain, the takeaways from the Trojans' first scrimmage Sunday night, and much more with our top takeaways from practice Tuesday.

In giving his assessment of the team's first scrimmage from Sunday night, Riley initially spotlighted just one name -- redshirt freshman safety Zion Branch.

"Zion Branch had a pick-6 and a forced fumble, really showed up well. He made some outstanding plays. If you ask me the one guy that really stood out, it was certainly Zion," Riley said. "Pretty cool obviously with his story. Didn’t have the ideal start to a career with the injury and just kind of fighting back from that physically and mentally. So it’s been cool to see him really gain some momentum here the last several practices."

Branch, of course, was one of the Trojans' biggest recruiting wins in the 2022 class that came together quickly after Riley was hired. He was ranked the No. 4 safety and No. 64 overall national prospect, and there was a thought he could compete for a major role last year in a pretty unsettled USC secondary.

But Branch tore his ACL during a summer workout and his season was done before it even started.

Junior standout Calen Bullock and veteran Bryson Shaw return as the incumbent starters at safety, while Max Williams played a major role last season between nickel and safety and is now working mostly at safety. So there's isn't necessarily a clear path to a role for Branch, but that may not matter if he forces his way into the picture.

At 6-foot-2, 210 pounds with the blend of size and speed coveted at that position, it's looking more and more likely that Branch will be a factor this fall in some capacity.

Riley wasn't the only one to single him out Tuesday, either.

When asked who impressed him in the scrimmage, Alexander -- the DT transfer still settling with the Trojans -- said "8 ... Zion Branch. He had a real good scrimmage."

"Zion's definitely improved a lot," Max Williams said. "... He's practiced consistently and then in the scrimmage just balled out, so definitely surprised a lot of people the way he's been playing."

Branch talked to reporters last week about what it's meant to him to be fully healthy and fully unleashed this camp.

"I feel like through this year I learned a lot mentally getting to be with Coach Grinch, getting to be in that meeting room, and then just learning from a lot of the safeties like Calen, B-Shaw, Max -- watching those guys last year really taught me a lot," he said. "... Getting to be out there competing with my teammates each and every day is just really like a blessing for me. I can't take any day for granted."

He wasn't the only standout from the scrimmage, though ...

While it was closed to media, we were able to piece together some details through interviews Tuesday.

The consensus being that the defense won the day, led by the pressure up front from that reinforced defensive line that has generated so much buzz.

"Defensively certainly had the upper hand overall in the scrimmage," Riley said. "There were some bright moments, but a lot of inconsistency out of the offense. Defensively, made less mistakes and made more plays overall. ...

"D-line certainly won the day in the scrimmage. It's been, I would say, more back and forth in the days, but right now we can roll through several groups on the D-line and there's not a ton of drop-off and there's kind of constant pressure in terms of the O-line having to perform, which is good."

That sentiment was echoed by several players as well ...

Said Max Williams: "The defense has definitely improved. If you would look back to how we performed last year the first scrimmage to this year in the first scrimmage, it was vastly improved. ... Definitely the run defense. The D-line up there is just ferocious, getting back there to the quarterback. Especially on pass plays, how they get back there, guys like Anthony Lucas, Jamil [Muhammad], Bear, who's been practicing recently, the D-line looks monster."

Said Muhammad, the RUSH transfer from Georgia State: "Scrimmage went well for me. I played faster, I got one or two sacks. I could have definitely did better in some areas, of course -- I mean nothing's perfect. But I'm just glad to be around a lot of guys who make plays and make me look good and I can also complement them as well. At the end of the day it was cool, even though we were dominating for most of the scrimmage, offense had their dominant moments and it's cool to realize we're all on the same team."

Said defensive lineman Jack Sullivan: "I think overall as a D-line, I think we really just brought the juice. We were energized for the scrimmage so I was proud of that. We definitely have to keep that going. We can't just settle on that one day, we've got to keep that going through the rest of camp and keep that preparation and momentum going to the first game."

That's the message defensive line coach Shaun Nua wanted to reiterate Tuesday, meanwhile.

"They played with good effort and good technique. They were having fun out there. They were just executing calls. Unfortunately, that was two days ago," he said. "I thought the offense got the better part of us today, though. The name of the game is what have you done for me lately."

One other notable defensive observation came from Riley, who said he was "pretty pleased with our tackling."

"A lot of times, the first scrimmage, the tackling is a weak area just because you’re out there in the open field for truly a number of snaps. It’s not thud. You’re not blowing a whistle. I thought we did a good job in space limiting some of the big plays offensively," he said.

As for the offense ...

"[Right tackle Michael] Tarquin had a really good scrimmage up front, [backup quarterback] Miller [Moss] had a really good scrimmage. Recovered well, we had a turnover early and then played really clean after that, thought he came back well. Ja’Kobi Lane had a really nice scrimmage, had a couple really nice catches, some big-time plays. Lake [McRee] had some really nice plays. Those are the ones I’ve kept in my head," Riley said.