Broncos roster breakdown: Defensive line

With the NFL's scouting combine set to open Wednesday and free agency to follow on March 11, today marks the sixth installment of a position-a-day look at where the Denver Broncos stand at each spot on the depth chart, the salary-cap commitments and where their needs are greatest.

Today: Defensive line

Thursday: Linebackers

In the Broncos' defensive fronts there are certainly more questions than answers right now. Beyond Terrance Knighton, Malik Jackson and Sylvester Williams, the Broncos have plenty to cross their fingers about and plenty of medical reports and possible options to consider.

If things work out, if the medical staff sees the recoveries the team expects and things go well, they will have a versatile, deep group that can adjust to almost any situation -- especially if Knighton, whose representatives have already asked for a new deal, picks up where he left off down the stretch in 2013 and into the postseason.

Jackson is an emerging player who has the ability to play with impact at both end and tackle. Williams was likely the team's most improved player from September to February and projects to be a starter in '14.

But the rub will be how Derek Wolfe (illness), Kevin Vickerson (hip) and Quanterus Smith (knee) emerge from their time on injured reserve. Because of Von Miller's knee surgery and Shaun Phillips' entry into free agency, Smith is going to have to be every bit of the pass-rush force the Broncos hope he can be.

If any of those three isn't up to full speed when the season opens, the Broncos will have a significant hole in their rotation.

The Alpha: At one time, Wolfe looked to be growing into this role, both on the field and off, but after he suffered seizure-like symptoms on a team bus ride to the airport in late November, he didn't play for the remainder of the season. So, it fell to Vickerson and Knighton to be at the front of the line at this position group. If Wolfe returns through the offseason workouts and into training camp at his former level of activity -- and that was the Broncos' expectation as this past season drew to a close -- he figures to step to the forefront again. But Wolfe was struggling at times even before he went on injured reserve after suffering a neck injury in the preseason, a scary incident when he was taken from the field by ambulance.

Salary cap: The Broncos have seven defensive linemen who finished the 2013 season on the team's 53-man roster or on injured reserve under contract for '14. Knighton's $2.75 million cap figure leads the way among the group with Vickerson's $2.266 million figure just behind. Williams, at $1.723 million and Wolfe, at $1.42 million, are followed by Sione Fua ($645,000), Jackson ($623,000) and Smith ($468,000).

Knighton had a $1 million roster bonus as well.

Pending free agents: Two of the Broncos' top three players in sacks this past season are unrestricted free agents: Phillips (10 sacks) and defensive end Robert Ayers (5.5 sacks, third on the team). Phillips signed a one-year deal on draft weekend last year and while the extra workload that came with all of the Broncos' injuries in the defensive front seemed to affect his play at times, he was one of best price/production signings in the league. Ayers has now finished his original rookie deal, signed when the Broncos made him the 18th pick of the 2009 draft -- the second draft pick of Josh McDaniels' tenure.

Who could stay: The Broncos have no significant cap issues to address at the position and while Knighton would like to cash in on his play over the last two months of the season, the Broncos are not expected to address his contract this year. Knighton and Vickerson are slated to be unrestricted free agents after the 2014 season.

Who could go: Ayers likely will have to look elsewhere to get his best deal. The Broncos would bring him back at their price because he is familiar with the defense. Phillips will be entering his 11th NFL season in '14 and while he helped the Broncos overcome plenty of injuries, they'll be looking to get a little younger up front. But if he's unsigned after the initial wave of free agency, the Broncos could look to sign him to a deal similar to the one he had this past season -- a $1 million base with some incentives at several sack totals.

What they like/want: Defensive coordinator Jack Del Rio likes big guys in the middle such as Knighton, Vickerson and Williams to eat up blockers, but he also needs some versatile inside-outside types like Jackson to make it all work when the Broncos move from their base look to some of their specialty packages with five, six or seven defensive backs.

Denver likes Smith's potential -- take a look at his three-sack game against an Alabama offensive line loaded with NFL prospects as a senior at Western Kentucky to see what's there -- and he will be looked at hard as the team goes through its offseason paces. The Broncos have bigger needs at other places and with Miller recovering from ACL surgery, the to-do list for Smith as an edge player figures to be a healthy one.

Need index (1 is low priority, 5 the highest): 3

They need some attention up front given the number of players coming off injured reserve with heavy workloads in their rotation. If all of them return without incident to the form that is expected, the Broncos are fine.

But history has repeatedly shown that's not something the team should count on. As a result, they'll have to give defensive tackles and edge rushers some looks heading into the draft.

There's enough uncertainty here to warrant a move or two as insurance.