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The Denver Broncos have to make tough decisions before the start of free agency. They have several needs this offseason, and defensively they’ll be looking for players who fit the new 3-4 defense.

The fulcrum of that type of defense is the nose tackle. At this time, Denver really doesn’t have a player locked in at that starting position for 2015.

Last year when playing a 4-3 under front, the Broncos featured players like Terrance Knighton and Sylvester Williams inside at defensive tackle. Other players who sometimes played defensive tackle for the Broncos include guys like Marvin Austin, Malik Jackson and Mitch Unrein.

This offseason, the Broncos will have an opening at the nose tackle position. There will be plenty of options for the Broncos, and they will need to examine each option closely.

What can the Broncos do at the defensive tackle position? Let’s take a look.

Broncos Free Agents

The Broncos have 13 unrestricted free agents to consider this offseason. The biggest name on the list is the biggest player: Terrance Knighton. “Pot Roast” has put together two strong seasons with the Broncos after getting benched during his final year with the Jacksonville Jaguars.

Jeff Legwold, from ESPN.com, reports that Knighton wants to stay with the Broncos. “Pot Roast” has told me on more than one occasion that winning is more important to him than money. Even though Knighton wants to stay, the open market may establish a price tag that is too high for the Broncos.

Mike Klis, from The Denver Post, believes the Broncos will allow Knighton to test the free-agent market.

Josina Anderson, from ESPN, reported last week that Knighton is getting frustrated with the process:

Just spoke w/ Broncos DT Terrance Knighton who's set to bcm a UFA. Very honest telling me he's frustrated w/ lack of communication w/ team. — Josina Anderson (@JosinaAnderson) February 19, 2015

Troy E. Renck, from The Denver Post, speculates the Oakland Raiders could show interest in Knighton. The move would make sense for both sides. Knighton had a career resurgence under Jack Del Rio in Denver, and Del Rio was the head coach of the Jaguars when Knighton was a third-round pick in 2009.

Mitch Unrein is also set to be an unrestricted free agent when the new league year starts. Known as a “team first” guy, Unrein is unlikely to draw the size of offer that Knighton will on the open market. Unrein could stick around in Denver for a good price, and he could compete at nose tackle or defensive end in the new scheme. Unrein is a hard worker whose veteran presence could be good for the locker room.

Outside Free Agents

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If the Broncos let Knighton go, they’ll look to other teams in order to fill the large void. This free-agent class has some big-name defensive tackles, but players like Ndamukong Suh will also come with incredibly huge contracts. Denver is unlikely to spend a ton of money at this position, and instead they should look for players with a cheaper price.

He may want to be paid like one of the top defensive tackles in the league, but Nick Fairley is unlikely to get such a deal on the open market. He finally started to play up to his enormous potential in 2014, racking up 14 tackles, one sack, one forced fumble and three quarterback hits over the first eight games. A knee injury prematurely ended Fairley’s season, but he was just one off the team lead with 16 quarterback hurries before he got hurt.

The Detroit Lions declined to pick up Fairley’s fifth-year option that would have paid him $5.5 million in 2015. Instead, they will let him hit the open market, where teams like Denver could be waiting. Fairley has to prove that he’ll pick up where he left off with a new contract and likely a new team. Weight issues and motivation have always been questions surrounding Fairley since he came out of Auburn in 2011.

A player they could consider bringing back is Kevin Vickerson. He was with the team from 2010 through 2013, but he was released in training camp last year. It was basically a salary-cap move that came down to keeping Vickerson or Unrein—and Unrein was the cheaper option. Vickerson signed with another team quickly and ended up spending the 2014 season with the Kansas City Chiefs.

Vickerson will play well no matter where he lines up. The Broncos asked him to drop weight a few years ago so he could play defensive end. He did so, and Vickerson was a quality asset at that position. They asked him to regain the weight so he could move back to defensive tackle in 2013. He once again starred at the position before a hip injury knocked him out for about half of that season.

Age and injuries are a concern with Vickerson, but he’s a quality asset who will come with a reasonable price tag.

2015 NFL Draft

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In addition to outside free agents, the Broncos must look at the incoming crop of college players to see if there’s a player they like at defensive tackle. The Broncos will have more than a few options over the first two rounds of the draft. The top of this draft should feature players like Leonard Williams (USC) and Danny Shelton (Washington)—both of whom could be top-10 picks.

At the end of the first round, the Broncos might find that Carl Davis (Iowa) is still on the board. With a skill set that is reminiscent of Vince Wilfork (New England Patriots), Davis could make for a nice pick—and a player who could compete for a starting job from day one.

Davis is a powerful player who can win with his hands and eat up double-teams regularly. He has a strong initial punch when engaging an opponent, and he does a good job of keeping his blocker off of his body. Davis did get worn down on film as games went on, so stamina is a concern.

He was a standout player for me at the 2015 Reese’s Senior Bowl, and that should help his draft stock. At this time, NFLDraftScout.com has him listed as a potential second-round pick.

In his latest mock draft at NFL.com, former scout Daniel Jeremiah has the Broncos selecting Jordan Phillips from Oklahoma. Phillips is a stout run defender who does offer a little bit as an interior pass-rusher.

The Broncos need a player like Phillips up front. Phillips is a mountain of a man, measuring in at 6’5”, 329 pounds. Lance Zierlein, from NFL.com, listed Terrance Knighton as Phillips' pro comparison.

Phillips eats up space and uses his length to disrupt passing lanes. He’s got good functional strength, and he’s more athletic than some think a big man can be. Phillips will need to improve his technique if he wants to win consistently at the pro level.

Summary

The Broncos have multiple priorities this offseason. They need to find upgrades for the offensive line, plus finding a nose tackle for the defense might be the top two priorities.

An option for the Broncos is to promote players already on the roster.

One of the players who might be able to play nose tackle is Sylvester Williams. The Broncos spent their first-round pick on Williams in the 2013 NFL draft, but he has yet to develop into an impact player.

In a private interview at the combine last week, I asked Elway if Williams could play nose tackle.

“Yeah, I think so. I think Sylvester is still growing. We still like Sylvester, and there’s a lot of potential there.” Elway emphasized, “If there’s any guy who can get it out of a player it’s our new defensive line coach Bill Kollar.”

Another player already on the roster is Marvin Austin. A second-round pick by the New York Giants in 2011, Austin bounced around the league to three teams before landing in Denver last year. If healthy, he has the size, motor and ability to eat up double-teams as a nose tackle.

Finding a starting nose tackle is arguably the biggest need the Broncos have this offseason. Time will tell if they go with one of their own free agents, an outside free agent, a pick in the NFL draft or someone already on the team.

All quotes and injury/practice observations obtained firsthand. Record/statistical information provided via the Broncos' media department unless otherwise noted.

Contract and salary-cap information provided by Spotrac. Transaction history provided by Pro Sports Transactions. Draft grades provided by NFLDraftScout.com.