CHARLOTTE – Walking off the practice field, Vernon Butler looks nothing like an NFL rookie.

At 6-4, 323 pounds, the defensive tackle has the look of a veteran. But look closer, and you'll see that he's toting the helmets of several veterans – a tradition as old as the game itself.

"It's good to be out here with guys I've watched on TV," Butler said.

Soon – the Panthers hope sooner rather than later – Butler and the other rookies will be ready for primetime.

"We're seeing the young guys assimilate very well to the way we do things, and they're fitting very nicely into the locker room," head coach Ron Rivera said after the seventh of 12 offseason practices that feature both the Panthers' rookies and veterans. "We've got a good group of young guys that are competing and that are pushing the veterans quite honestly. It's going to be very strong competition."

The rookies took to the practice field for the first time two weeks after the draft at Carolina's annual rookie camp, which pitted them against each other, a large contingent of invited tryouts and a handful of returners.

Some of the rookies did spend the following week with the veterans at the conclusion of Phase Two of the offseason workout program – a period in which the offense and defense don't intermingle on the practice field. But the next week it got real with the arrival of Phase Three, which brought with it organized team activities – the start of a four-week stretch that looks a lot like training camp, save the physicality.

That's probably for the best for the rookies, who have plenty of mental obstacles to overcome first.

"They're smart, so you don't have to tell them a lot of times," cornerback Robert McClain said.

McClain, entering his seventh NFL season, is working closely with a trio of drafted corners – second-round selection James Bradberry, third-rounder Daryl Worley and fifth-rounder Zach Sanchez.

"They're doing well," McClain said. "They're going to make mistakes – they're young – but they are working hard. If they make a mistake, they're going full speed doing it."

The rookie cornerbacks are thankful to have somebody like McClain in their corner.

"He has a lot of experience, so I'm just trying to learn from the things that I not only see him do but also the things he talks about in the meeting room," Worley said. "He helps with knowing where to have your eyes on each play and what to expect."

The rookies, believe it or not, can also learn from each other.

"If I make a mistake, James can hear the coaches talking to me, or vice versa," Worley said. "It makes our learning process a little bit easier."

Easier, yes, but not easy. Being able to learn from the veterans in your position group does bring a certain comfort level, but learning takes a different form when facing a veteran on the other side of the ball.

"Going against guys like that makes you better - guys like Thomas Davis and Luke Kuechly," said tight end Beau Sandland, the Panthers' seventh-round draft choice. "There's the old adage, 'Iron sharpens iron.' You want to go against the best of the best."

But it's nice after those battles to be able to go back to your meeting room and compare notes with one of the more notable names in the game.

"Any time you can spend with the veterans – the guys who have been here multiple years – is good, especially in our room with guys like Greg (Olsen) and Ed (Dickson)," Sandland said. "I consider myself lucky, being a rookie and coming into a room with that much experience.

"I'm just trying to be a sponge."