ENGLEWOOD, COLO. -- Competing against a quarterback like Peyton Manning, is in many ways, a defender's worst nightmare.

Sticking with NFL wide receivers in coverage is no easy task, regardless of the quarterback. It becomes that much more difficult against a quarterback like Manning, cornerback Champ Bailey said.

"One thing about him is, you can cover a guy and his ball placement is so perfect," Bailey said. "It's frustrating, because when you're all over a guy and he puts a ball here, you can't do anything except break it up or watch him catch it. There aren't a lot of turnover opportunities."

Covering receivers targeted by Manning is so challenging that Bailey expects it to make playing against other quarterbacks on game days seem easy by comparison.

"Not a lot of quarterbacks are that sharp," Bailey said. "I'd say 90 percent of them aren't that sharp. We're going to face some of those 90 percent, and as long as we're covering our guys in practice close enough to make a play, we'll make some plays in games."

Manning's not the only Bronco testing Bailey and the defense during the week. Bailey said tight ends Jacob Tamme and Joel Dreessen are versatile players who make the defense work hard on every snap.

"It's tough," Bailey said. "They create matchup problems across the board, but we thrive in that because we have a lot of guys with a lot of pride on defense and we don't want to let them beat us. They have a lot of talent, but it gets us ready for Sunday."

Through one preseason game, it looks as though the Broncos' effort on the practice field is paying off. Denver held Chicago to just three points in Thursday night's preseason opener and allowed the Bears to gain less than 150 yards of total offense. But the defense still has room to improve.

"It was a good start," Bailey said. "That's all it was. We can't look too much into it. We've got to get better. There were some things we can iron out. They didn't have all their bullets flying that week. We take the win in stride and just try to get better from that."

Bailey said the preseason win opened his eyes to a lot of things he's unable to see during practice. And he liked what he saw.

"As a team, you can see the guys who can play football, and you really can't tell until those lights are on in a night game and the cameras are on you," Bailey said. "That's the only way you can tell. I learned a lot about a lot of my teammates. One thing I do know is we have a lot of good players on this team."

THOMAS MAKING PROGRESS

Tight end Julius Thomas didn't need long to crack the Broncos' starting lineup. A fourth-round selection in the 2011 NFL Draft, Thomas earned a starting nod for the team's regular season opener. But an ankle injury suffered the following week brought his rookie season to a screeching halt.

In the offseason, Denver picked up free agent tight ends Jacob Tamme and Joel Dreessen. But Thomas said he doesn't let his injury or competition get to him.

"It's always hard," Thomas said. "But you're going to get an opportunity. You never know when it's going to come. I was starting last year and next thing you know, I'm down. I'm just going to do what's expected of me and wait for my chance to get an opportunity."

Though he has not yet returned to full speed, Thomas said his ankle has come a long way since last year.

"I'm at about 80 percent," Thomas said. "I definitely have a lot more strength still to build in that leg from the ankle on up to the hip. It's coming along. It feels better than it felt at any point post-injury last year. I'm encouraged."

With a pair of veterans in Tamme and Dreessen at his position, Thomas has not one but two experienced players he can emulate.

"It's great to play with those guys," Thomas said. "Tamme's played in Peyton Manning's offense for a long time, so he has a lot of insight. He knows what Peyton wants, how to execute the offense. Joel is a professional. The guy works so hard on his assignment, how to execute, I think that's been teaching me how to approach the game in the meetings, walkthroughs. I think it's going to pay off a lot."

BANNAN BOUNCING BACK

Two weeks before he was set to return to action in Denver, where he started all 16 games in 2010, a routine wind sprint went wrong for 11th-year defensive tackle Justin Bannan.

"I was training two weeks before camp, just trying to do what I always do, which is to get into the best shape of my life," Bannan said. "I was doing sprints, and I was literally coming down to my last sprint, and it popped on me."

The calf injury has made even the basics of defensive line play — coming out of a stance -- a challenge. But Bannan was in full pads again Monday morning.

"I've just got to ease back into it, get the leg used to firing off the ball and all those kinds of things," Bannan said. "I came out at the beginning of camp, unfortunately I had a couple setbacks with it. It was one of those things where I felt like I could go; my mind was telling me one thing, and my body was telling me something different, so I had to listen to my body."

Though his calf has been a hindrance, Bannan said this camp has still been much easier on his body than the 2010 training camp.

"The camp in 2010 I thought was probably the hardest camp I ever had," Bannan said. "It was two-a-day, every day, full pads, with conditioning afterwards with your pads on. That was extremely difficult. This camp, because of the new CBA, isn't quite as physically demanding, and as an older player, I think it's smart."