In today's college football world, age really isn't much of a factor. The excuse of being young in the locker room is almost a crutch these days.

The SEC is no different, as a handful of true freshmen have come in made immediate impacts. Johnny Manziel might have been a redshirt freshman when he shattered records at Texas A&M and won the Heisman Trophy last year, but he really was a frosh at heart with no collegiate experience and having to learn a brand new offense before even taking a meaningful snap.

That's why freshman defensive end Robert Nkemdiche is expected to make a Manziel- or Jadeveon Clowney-like impact this fall for Ole Miss. It might not be fair and it might be a little extreme, but when you're the consensus No. 1 high school football player and have the physical ability to step on the field immediately, it comes with the territory.

For Nkemdiche, his first weekend of practice with the Rebels appeared to be a success. It's early, and players really are just going through the motions at this point, but from a physical standpoint, Ole Miss' staff was very, very impressed with what it saw from the youngster.

“He’s physically gifted enough to play, so it’s all about can he understand what we’re trying to accomplish, what his assignments are,” coach Hugh Freeze said over the weekend. “If he can get that, there’s no question he can physically play. [The defensive coaches] better be trying to get him ready.”

That will be defensive line coach Chris Kiffin's main objective when it comes to Nkemdiche. The good news for Kiffin is that the physical part should make his job easier. Nkemdiche already has the speed, size and strength to play right away. This spring, Freeze told ESPN.com that the advantage his staff has with Nkemdiche is that it doesn't have to worry about packing on pounds or getting his body into better shape. He's already there, but it's all about the mental part of things.

"You don't have to do anything to his body to make it already what it needs to be to play in this league," Freeze said in March. "He's so far ahead of the curve with that. Now, it's just a matter of him being mentally able to turn his athletic ability loose because he's confident in what he's doing."

For Kiffin, he said he isn't too worried about Nkemdiche adjusting because of the attitude he carried onto the field in high school. Studying Nkemdiche's high school film, Kiffin discovered that while Nkemdiche wasn't always perfect with technique or positioning, he never really stopped. His continuous motor eerily reminded Kiffin of Nkemdiche's brother, Denzel, who had a breakout year at linebacker for the Rebels last year.

"If he plays anything like his brother, the kid's going to be phenomenal," Kiffin said. "You can just tell by film, by the way they act and talk that they are so close (as players on the field) that I just know that's the type of player we are getting in effort. If you can come in as a freshman and give that kind of effort with the size and speed that he brings, then he's going to be able to do it.

"I really do hope that he's playing a lot or starting on opening day. That's the plan for the No. 1 player in the nation.

"I don't think this kid has any chance of being a bust because of the mental side, along with the physical tools."

During Monday morning's practice, Nkemdiche was already getting some reps with the first-team defense. Expect that to increase, and expect coaches to let Nkemdiche be himself, as they try to build two parts of his game this fall.

"I see him has a dominate force to stop the run and rush the passer," Freeze said. "If he can do those two things, we don't need him to do a whole lot more."