ENGLEWOOD, Colo. -- Defensive Coordinator Jack Del Rio is understandably excited to once again work with Head Coach John Fox. The two worked on the same staff in Carolina back in 2002, when Del Rio served as defensive coordinator during Fox's first season as an NFL head coach.

"The game evolves and you're constantly evolving with it," Del Rio said. "It's cyclical at times. Things that were en vogue a couple decades before will come back into the game. It's been a good experience. The last time around I was fresh off my time in Baltimore and got with Coach Fox, I really learned a lot from him and tried to apply that and make that ours. Really it's been the same approach here."

If 2002 was any indication, the Del Rio-Fox connection will make for plenty more long afternoons for opposing quarterbacks already wary of linebacker Von Miller and defensive end Elvis Dumervil, who combined for 21 sacks in 2011.

Under Fox and Del Rio, a Panthers defense that surrendered a league-worst 371 yards per game during a 1-15 2001 season transformed into a formidable unit. That season, NFL Rookie of the Year Julius Peppers -- who got to the quarterback 12 times in 12 games -- was one of five Panthers to tally at least five sacks as Carolina finished second in the league with 52 quarterback takedowns. The Panthers' 2002 D also gave up the second-fewest yards in the NFL and allowed less than 19 points per game after surrendering nearly 26 points per game the previous season.

"We've got a good defensive staff, and with Coach Fox, obviously a lot of experience," Del Rio said. "Then I have a lot of experience and we've pooled that together and made this our defensive system for this year. We're working hard at installing it and getting it repped and sharpened up right now."

DTs BEEFING UP

While it remains uncertain who will man the bulk of the snaps at defensive tackle this season, one thing is clear: Del Rio wants his tackles to be hefty enough to anchor the interior of the defensive line.

"We want some size in there," Del Rio said. "I like big D tackles."

Defensive tackle Kevin Vickerson appears to have taken that advice to heart.

"Vickerson has added some good weight," Del Rio said. "It should help him. One of the conversations early that we had was, 'Hey, what do you want me to weigh?' I said, 'Well, the guy I looked at on film last year looked like a defensive end that was moved in there. It was a narrow body. We'd like to see a large rear end in there.' So he's made it a little bigger (laughs). We're trying to make sure it's good weight he's adding. He's working hard in the weight room and getting himself into shape."

Another tackle who has impressed Del Rio during OTAs has been Sealver Siliga, a 307-pounder entering his second season with the Broncos.

"I like Siliga," Del Rio said. "He's a young guy. It's hard to know too much about D-line play until you get into pads, but he appears to be a stout interior defensive lineman. A guy that can give us a little bit of a presence in there, eat up blocks and give us a little bit of a push in the middle. His demeanor is excellent. He participated in the rookie minicamp. Everything we've asked of him in terms of weight room, conditioning, studying and then work on the field, I think he's been really good. Our hope is we can bring a guy along like that, develop him and have him blossom for us. We're going to grow a few of these players that have been here and help them be better this year. We need that. We need some of these guys to take a step forward. I'm hopeful he can be one of those guys."

PATIENTLY AWAITING WOLFE

Speaking of defensive tackles, it will be another few weeks before coaches get to see second round draft pick Derek Wolfe, a 6-5, 300-pound defensive tackle out of Cincinnati.

Wolfe, who the Broncos drafted with the 36th pick in the 2012 NFL Draft, doesn't graduate until June 9. So by the time the first player Denver selected in this year's draft is able to don the orange and blue, his defensive coordinator will be ready to put Wolfe to work.

"We're excited to have him and we'll get our hands on him soon," Del Rio said. "I know he's anxious. He really wants to be here, but we're just abiding by the rules. He'll get here in short order."

Del Rio said he's not frustrated with the fact that Wolfe isn't yet at Dove Valley, as he knows the rookie has been staying in shape. He even has the team's playbook, though the defensive coordinator knows there's "only so much that you can do on your own with a playbook."

"Really, he needs to do it," Del Rio said. "We'll play catch-up when we get him here and do the best we can. I know he's very eager. One of the things that he's known for is tenacity and the way he approaches every play. I think you'll see that once he gets here. I know for now he's just got to kind of bide his time, do what he can to be familiar with the concepts that we're going to be asking him to do and get himself physically ready."