ENGLEWOOD, Colo. — With a core of five Pro Bowlers on defense, the Broncos have the base in place to improve in the coming season beginning with training camp, but there are still questions to be answered before the season starts.

The focus of these questions for Head Coach Gary Kubiak is the defensive line, he said on Thursday. Overall, the depth of the second line of defense and the secondary have impressed him. But the questions that remain about the line revolving around getting defensive end Antonio Smith up to speed at camp and facing Derek Wolfe's impending four-game suspension aren't necessarily daunting to Kubiak as he prepares for the season.

"I am really excited about our defense. We have some great depth on that side of the ball when you look at the linebacker position and you look at the secondary," Kubiak said. "Obviously, the defensive line has a few concerns as we head into training camp right now, but I'm very excited about the position."

Outside linebacker DeMarcus Ware said that in the middle of the line Sylvester Williams has "really stepped up to the plate" in moving into the solitary nose tackle position after last year's 4-3 defense with two defensive tackles inside.

"He's sort of progressed to a point where, now, you look at him in practice and you're like, 'You're out there making plays now. You're doing what you need to do,' I say, 'but you have to do that every single day when you're out there playing.' And, I mean, I'm ready," Ware said. "I know he's going to be that guy for us and I don't think the defensive line is a question at all."

Kubiak has a high level of confidence in the coaches guiding the defensive linemen.

Throughout the offseason, Kubiak praised Kollar, who worked with him in Houston. In June, Kubiak said, "Bill works the heck out of them. That's his belief—when you play hard upfront, you're going to play good. That's way he coaches and guys have responded to him very well."

Kubiak, Kollar and Defensive Coordinator Wade Phillips worked well together in Houston, and they hope to continue that in Denver. Phillips has said his focus is on utilizing every player's skills to the best of their ability.

"I know that Wade will put these guys in. It's very simple: They do what they do best," Kubiak said. 'When you have the chance to have the edge players that we have with [OLB] Von [Miller] and [OLB] DeMarcus, and then you go add [OLB] Shane [Ray] to that mix we'll have the ability to make people get rid of the ball very quickly. I like the group, I think that they've had some success and I think that Wade will add to that."

Ware already knows what Phillips can do having played for him in Dallas and flourishing in his defense, and he knows Phillips can have a similar impact in Denver.

"I think it's that type of time right now where when you change from a 4-3 to a 3-4, you're able to use guys like me, Shane Ray and you can use Von and just move everything around and getting pressure," Ware said. "We're really good athletes, can rush the passer, so to be able to have all of us in there playing, I think we're going to be a lot more effective and be able to reek more havoc on the offenses and convert into the 3-4. I think it's going to be a good thing and it's all about that Orange Crush."

Amid the concern on the line, Kubiak said DE Vance Walker's versatility is a major help and that DE Kenny Anunike stood out in OTAs previously.

Elsewhere on the defense, the health of expected starting inside linebackers Danny Trevathan and Brandon Marshall has also been a key development.

The two had previously said they were aiming to be back for training camp, and Kubiak confirmed that they had been able to work with some of the rookies who had reported to camp on Monday. They're not going to receive an unabridged workload, Kubiak said, but they'll be doing more than what they saw in OTAs.

Ware noted that Marshall and Trevathan's absence has been difficult given their talent, but the opportunity to get linebackers Todd Davis and Steven Johnson offers them a chance to build invaluable depth.

"They know how to play; where to fill the gaps at. They do everything really quick. And with Todd and Steve in there, at first you look at it like, 'I'm not used to those guys really [to] carry on the huddle.' Until OTAs and training camp you get a little bit used to it. And those guys start calling the plays and start getting comfortable and [learn] how to do things. And they start getting more comfortable in demanding more out of us. So now that depth is almost like four starters now. And that's going to be really great for us."