ENGLEWOOD, Colo. -- Ask any NFL quarterback and they'll tell you Von Miller is a pretty scary dude.

The runner-up Defensive Player of the Year in his second season, Miller hounded opposing signal-callers for 18.5 sacks and six forced fumbles in 2012.

But after a disjointed third season limited by suspension and injury, Miller almost sounded like a rookie when talking about his expected return to the field on Sunday.

"I was super nervous in the preseason game," he said Wednesday. "That's something I've been trying to work on in practice, getting the nerves going and just trying to calm myself down at practice."

"Thinking about the game and trying to put myself in that moment in practice and just trying to come out of it when I'm out there on the field."

The nerves are undoubtedly heightened by the fact that Sunday will be Miller's first extended action since tearing the anterior cruciate ligament in his right knee in December. And as he points out, he hasn't played in a season opener since the 2012 season after missing last year's game against the Ravens due to suspension.

Add in the amount of work Miller has put in this offseason to work back from the injury, progressing from individual drills to team work and eventually game action, and it's easy to understand why he might have some jitters.

Encouraging for the Broncos, however, is that none of the anxiousness for No. 58 is related to his knee. He says he's had full confidence in the injured leg for some time now.

"I mean I was there in the offseason," he said. "I was there at like 15 weeks."

"I don't know how many months I am now, but I'm going out there and playing. I can play football. I can do what I do to the best of my ability, with the knee brace or without the knee brace."

Another defensive starter making his return from an ACL injury against the Colts, Chris Harris Jr., doesn't quite know what emotions to expect on game night. But having missed all of the preseason, there's one thing the fourth-year corner is sure of.

"I'm just ready to hit somebody, man," Harris said. " I've been waiting to hit somebody and just turn into a monster out there. That's what I'm waiting for."

Harris had surgery about a month after Miller, but progressed in his recovery fast enough that his timeline nearly caught up to the linebacker's. Despite not playing in the preseason, Harris expects to be fully ready on Sunday, "covering like how I usually cover." When asked about facing Andrew Luck and the Colts in his first game back, Harris didn't exactly sound daunted by Indy's offense.

"I get a warmup game every day with Peyton Manning," Harris said, smiling. "So going against them and [Demaryius Thomas] every day, that's been great work for me. I feel like if I can cover DT and Emmanuel [Sanders], I can cover these receivers."

The corner's return to the field marks the final puzzle piece of the 2014 Broncos defense, which will be seen in its full construction for the first time this weekend. Even though Miller returned in the preseason, he played just nine snaps against the Texans, while Harris and third corner Kayvon Webster missed the game.

After an offseason of excitement about new defensive additions and hours upon hours of rehab put in by Miller and Harris, Sunday's game should provide the first true impression of this unit as a whole.