LOS ANGELES (AP) — After passing on the chance to enter the NFL early, cornerback Iman Marshall and linebacker Cameron Smith are determined to make the most of their senior seasons at No. 15 Southern California.

While the Trojans saw a significant talent drain after winning their first Pac-12 title since 2008 last season, with quarterback Sam Darnold, running back Ronald Jones II, wide receiver Deontay Burnett and defensive lineman Rasheem Green all declaring for the NFL draft early, Marshall and Smith decided to return to school and address weaknesses in their play.

For Smith, it meant losing weight and showing NFL teams he can be a three-down linebacker. For Marshall, it meant showing he has the technical skills required of his position and doesn't just rely on his physical ability. With the season opener against UNLV on Sept. 1 looming, both like the progress they have already made in reaching those goals.

"Why come back here and do the same thing? We're put in a unique situation to recognize the possibility of playing at the next level last year, and I think for both of us swallowing our pride and realizing we have things to get better at and not wasting time with it," Smith said.

Defensive coordinator Clancy Pendergast believes returning for their final season can only help Smith, a preseason second-team All-American, and Marshall, who has six interceptions in 36 career starts. Pendergast, who has coached in the NFL with Dallas, Cleveland, Arizona, Kansas City and San Francisco, sees them getting more out of preparing to be starters in college than being a backup or fighting for a roster spot.

Pendergast pointed to the success Smith has already had in rebuilding his body. He has dropped more than 20 pounds after playing at 250 pounds last season, and credits it for his increased energy and being better able to defend sideline to sideline.

"This is the lightest I've ever weighed since my sophomore year in high school. I feel great," Smith said.

Smith regrets waiting so long to focus on nutrition. He is making a point to stress its importance to the underclassmen, which reflects Smith's growth as a leader.

"I think something that I lacked last year is the confidence to be more of a mentor," said Smith, who was voted a team captain for the second consecutive season. "Just giving my wisdom and not being afraid to speak up, and giving them advice about what to expect and how to make this situation last and what to do differently or whatever."

Marshall has always been an athletic specimen at 6-foot-1 and 205 pounds, traits that are highly coveted in the NFL with the push toward bigger wide receivers. But he knew he had plenty to prove after not recording an interception last season.

"It was just understanding my criticism and understanding what the coaches expected from me, and taking that into consideration and having an honest evaluation with myself," Marshall said of his decision to return to USC.

Safety Marvell Tell III said Marshall's technique is the best it has been. Tell is even more impressed with how committed Marshall, referring to him by his nickname of "Biggie," is to making the most of every opportunity, whether it is lining up against starting receiver Michael Pittman Jr. or a walk-on with the scout team.

"His drive right now is incredible," Tell said. "I've been around Big for a long time, you know, high school and whatnot. But his focus right now is incredible, and it's rubbing off on guys. Even rubs off on myself."

Smith said Marshall has had a different demeanor since deciding to return to USC. He said what Marshall has done on the field, in meetings and in the weight room over the past eight months has been the best stretch of his career.

"I think I'm pushing towards that as well," Smith said. "No wasted time, just getting better in the things that I looked into getting better at. And that's why I came back, and it's been great."

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