Cameron Smith had his best season yet in the middle of USC's defense last fall, leading the team in tackles, setting career-best numbers and having the kind of campaign the Trojans would surely be pleased to see him repeat in 2018.

But that's not the way Smith is approaching it.

"Why come back here and do the same thing?" he said after practice Wednesday, when asked if his mentality has changed at all after choosing to hold off on the NFL Draft and return to school.

So Smith shed "about 22 pounds" from his frame since January, dropping his weight to 233. (He's listed at 250 in his official USC bio).

Sure, it's that time of year when college coaches across the country are quick to note how a player is in the best shape of his life right now (as USC coach Clay Helton indeed did with Smith), but in this case it looks to be more than coach speak.

"I've wasted no time in getting better at the things I want to get better at," Smith said. "I feel like I have a lot more energy in being able to run sideline to sideline, and at the Mike position we're forced to speak and yell and also play. I think it's just allowed me to do all that at a higher level than I have been. This is the lightest I've weighed since my sophomore year in high school so I feel great.

"The biggest thing for me, which I wish I would have done two years earlier, was just eating differently. ... Right now, I'm just focused on doing everything right on and off the field."

How exactly that manifests on the field is yet to truly be seen as Smith has only been back in the flow of practice for the last couple days after missing most of camp with a pulled hamstring. The injury was never viewed as a serious concern for his availability in the season opener, and he confirmed Wednesday that he feels 100 percent.

"I wouldn't be back if I wasn't. I am exactly where I want to be," he said.

And exactly where the Trojans want him, as an irreplaceable veteran presence in the middle of the defense. As the guy who's racked up 273 tackles over the last three seasons, including 112 stops and 11 tackles for loss last fall. And as a respected leader voted a team captain for the second straight year.

"He's just one of those guys that you know what you're getting every day," Helton said. "He's just constant leadership and constant production. That's why he's a captain. You know what you're getting from him each and every day."

Meanwhile, Trojans defensive coordinator Clancy Pendergast says he can notice the difference in Smith even though the middle linebacker has missed most of camp.

"I think he's moving better and I've been able to see him now a couple days, because he missed a lot with the pulled hamstring, but he appears to look better in the individual drills and 7-on-7s and the areas where he's playing in space," he said. "So I'm real proud of him, and [he's] really been a fun guy to coach from where he was coming off the knee injury in 2016 to going from middle linebacker to dime and then last year playing the middle again. And now he's got a full year under his belt playing in the middle to where he's not just seeing half the field -- he's seeing the whole field. I think he's going to have an opportunity to have a real good year this year."

That's a widely-shared assessment. Smith was named a second-team preseason All-American by the Associated Press on Tuesday.

As to Pendergast's assessment, though, Smith said his film study is another area he looked to improve heading into his senior season and he also tried to take whatever he could from his time as a spectator this month.

But he was happy to participate in his first live reps since spring practice, happy to be back in the middle of everything again this week and eager to show what all that focus and emphasis in the offseason was building toward.

"You never really realize how much you want to practice or play until you’re on the sideline watching everybody else play," Smith said. "... I think that kind of was, honestly, in a good sign from a crappy situation, it was a good way to start this year. Just because I got the feeling of being out, and I don't want to [have that again]. I just feel refreshed and ready to go."