It was a quarterback’s dream. It also demanded the hardest physical preparation Carden had ever experienced. East Carolina was used to a slower pro-style offense from the previous Skip Holtz regime, and the roster was ready to buy into Riley’s no-huddle ideas but didn’t fully understand what it took. In offseason conditioning, Carden said, they’d be required to sprint a lap around the field within 55 seconds, then rest for 40 seconds, then repeat. Six times.

A decade after growing into the 2014 AAC Offensive Player of the Year, Carden — now a realtor and high school football coach in Idaho — sat to watch his old coordinator lead USC into December’s Holiday Bowl matchup with Louisville and felt the tugs of memory. The Trojans were down to 53 players on their roster, and Caleb Williams and key receivers were out of uniform and out of mind, and Riley cooked up a spread-out game plan that let longtime backup Miller Moss simply play free in a six-touchdown performance.

And Carden saw an old version of himself in Moss’ shoes, young ambition firing again in Riley’s scheme a football life later.

“It was a little bit less pre-formation movement, a little less motion, and a little more to say, ‘Let’s stretch the defense vertically, let’s get some good reads for our quarterback, and let’s let him just sling it,’” Carden said. “And I thought that was really cool. That reminded me a little more of some of the ECU days.”

An unprecedented test in the 40-year-old Riley’s meteoric coaching rise is here, with USC’s foray into a new conference that boasts a radically different brand of football than his program’s strengths across two years in Southern California. And much has been made, both in national conversations and within USC’s own walls, about the philosophical need to build a more physical defense and bulk up for the Big Ten.

Those who’ve crossed historical paths with Riley’s scheme, though, see another side to that coin: How will Big Ten defenses, cushioned by years of lining up against slow and middling attacks, adjust themselves to one of the most explosive offensive minds in recent collegiate football memory?

Caleb Williams, and all his off-platform Heisman brilliance, is gone to the land of Hard Knocks in Chicago. Moss, a fourth-year former backup whose brilliance lies in timing and precision, is who remains. And Riley’s offense will shift again with Moss, just as it did with Williams, just as it did with Baker Mayfield and Kyler Murray and Carden and the legion of quarterbacks who’ve been molded under his tutelage. But his principles and aggressiveness will remain the same in the Big Ten, former players and coaches feel.

And Riley has made it clear, too: USC will change on its own terms. His own terms.

“I don’t know, I feel like sometimes, it gets made out in the media that the Big Ten is, like, some wildly different deal,” Riley said in the spring, part of a response when asked about USC’s adjustments to a new conference.

“Like, it’s football, it’s still — so a couple of teams play with one more tight end,” he continued. “Like, big deal. I think for us, it’s more our evolution as a program.”

‘There couldn’t be, probably, more expectations for him’

The signs peek through, past the sheer of Southern politeness, when Riley is doubted. His lips tighten. His eyebrows bunch. When posed a prying question or a challenge, he’ll often deliberate with a prolonged um.

The signs peeked through in late July, not so subtly, sitting in a podium in front of a swarm of media in Indianapolis at the Big Ten Media Days. A reporter asked Riley about a couple of Big Ten coaches’ comments on West Coast teams joining the conference: They enjoyed the sun too much, the reporter referenced, or couldn’t play in the cold, or couldn’t defend the run.

“Um,” Riley replied, in a dismissive monotone. “I don’t know. I really don’t care. We’ll find out in the fall.”

The same conviction has been there, since he was a 20-something wunderkind of a student assistant at Texas Tech treasured by Leach. Under the legendary coach, Riley grew into the wide receivers coach at Tech within a handful of years, and in the winter before his final year working under Leach, Riley gave a 45-minute speech at a coaches’ convention around the importance of the “four-verticals” concept to Texas Tech’s scheme. He called it “Six,” because, simply, it was designed to net six points.

In the audience, then-East Carolina receivers coach Donnie Kirkpatrick was enraptured.

“Man, you wanted to listen to him, and you believed what he was saying,” Kirkpatrick gushed.

A year later, when Riley took over as East Carolina’s offensive coordinator, the first play they installed as a part of his grand design was “Six.”

OK, Kirkpatrick thought, at least I know one.

He came to know plenty more, including a havoc-wreaking “mesh concept” — loosely defined by underneath receivers darting for crossing routes — so effective that Riley once said at a coaching panel, ”If we run mesh 100 times all year, there’s going to be probably two out of the 100 that it’s not open.” In his origins as an offensive coordinator, Riley reflected last week after a USC practice, East Carolina didn’t have the talent or personnel of rivals like NC State or North Carolina. So he designed the Pirates around playing fast, and spreading defenses out, and attacking individual defenders.

If they faced press coverage, no matter if it was a third-and-short, Riley would call a deep shot to a one-on-one matchup. If they hit a big play, they’d race back down to the line of scrimmage, never losing tempo. When they played Virginia Tech, one of the best defenses in the nation, Riley operated full throttle from the first play, Kirkpatrick said.

There was failure, of course. East Carolina finished with losing records in Riley’s first two seasons before eventually rounding into one of the better offensive units in the nation, and the coach spoke of those days last winter with slightly-graying hair and a reflective tone. He rode the “emotional rollercoaster” then, Riley reflected, without the perspective of a true lifetime in football.

“There was plenty of pressure then — like, if he’s not successful, they better figure out a new guy,” Carden said.

There is plenty of pressure, too, as a 40-year-old at USC, in the third year of Riley’s often-self-described program “rebuild” that can no longer reasonably be dubbed a rebuild after a third year. After years of defensive criticism dating to his days at Oklahoma, he cleaned house come the winter, bringing in a highly touted new staff and repeatedly referencing a shift in physicality in his program. And his offensive style, unrelenting throughout his career, will be tested in the cold and the wet of the Big Ten.

“This is a big year for him,” Carden said. “I think he understands that. Obviously, the team understands that. There couldn’t be, probably, more expectations for him.”

“But I think he loves that.”