NFL Free Agency 2016: Ranking Top Available Defensive Linemen

The official start of the 2016 NFL year is now only days away. On March 9 at 4 p.m. ET, the new fiscal year will kick off, and so will the latest edition of free agency.

There is a lot of talent and depth to be found among most positions in this year's market—and the defensive line is no exception. Several NFL teams will be able to land strong depth and quality starters for their defensive fronts. A few will even have the chance to land some legitimate stars.

Is your team looking for a young up-and-comer with some pass-rush potential? Newly crowned Super Bowl champion Malik Jackson could be your guy. Need a seasoned run-stuffer to clog the middle? Terrance Knighton might just be your man.

When it comes to defensive linemen, this year's free-agent class has them in all shapes, sizes and skill sets.

Today, we're going to look at the top defensive linemen headed toward free agency and rank them based on factors such as past production, injury risk, age and physical potential.

Do you agree with our list? Be sure to let us know in the comments section.

Honorable Mentions

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A number of defensive linemen are headed toward free agency who can have an impact in the right system but fall short of making today's list.

Veteran defenders such as Haloti Ngata, Kevin Williams and B.J. Raji can help bolster a team's run defense. Defensive end Chris Long could potentially help strengthen a team's pass rush—he has 54.5 career sacks—but his recent injury history will be a factor.

Greg Hardy has the physical tools to boost a pass-rush unit, but his off-the-field concerns may be too much for potential employers to overlook.

Players such Paul Soliai, Randy Starks, Jeremy Mincey and Ahtyba Rubin can fill depth needs or even start in the right defense.

We also have to take a moment to recognize defensive end Olivier Vernon, who racked up 61 tackles and 7.5 sacks with the Miami Dolphins this past season. He'd easily be near the top of our list, but he's technically not a free agent.

The good news, however, is that interested teams will still have a good opportunity to snag Vernon since the Dolphins hit him with the transition tag. If Miami cannot match another team's offer, the Dolphins will receive no compensation in return.

10. Charles Johnson, Defensive End

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Defensive End Charles Johnson won't turn 30 until later this year, but he has nine seasons worth of wear and tear on his 6'2", 282-pound frame and is coming off a down season. Hamstring injuries limited him to nine games with the Carolina Panthers during the 2015 regular season, and he finished with just 12 tackles and one sack.

It's just difficult to tell how much Johnson has left in the tank at this point, which is why he comes in at the bottom of our list.

However, there is the possibility that Johnson—who has 63.5 career sacks—can regain past form. He did have five tackles, one sack and one forced fumble in Super Bowl 50, after all. This is why the Georgia product still makes our list.

In fact, there's a good chance the Panthers might have held onto Johnson if not for his $15 million cap hit, per Spotrac. General manager Dave Gettleman certainly had kind parting words.

"Charles was an impact player for the Carolina Panthers for a long time, both on and off the field," he said, per David Newton of ESPN.com. "His statistics speak for themselves, and as a team captain he led the way you want your leaders to lead—by example."

Johnson can be a leader on just about any defense, and if the right team is willing to gamble on him, he might just go back to being a disruptive defensive force.

9. Robert Ayers, Defensive End

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Defensive end Robert Ayers ranks high on our list because he has the physical potential to be a productive pass-rush specialist. He's coming off a strong season with the New York Giants, producing 41 tackles and a career-high 9.5 sacks.

Pro Football Focus rated Ayers seventh overall among 4-3 defensive ends for the 2015 season.

The problem for Ayers is that he is 30 years old and appears to just now be hitting his stride as a pass-rusher. The former first-round pick's previous career high was five sacks in a season. Another issue is availability—the last time Ayers appeared in all 16 games was during the 2011 season.

Still, teams need, want and love pass-rushers, and Ayers stepped up and owned the role with the Giants last season. At 6'3" and 275 pounds, he has the physical tools. It will just be a question of whether he can continue building on his breakout season.

If a team is confident that Ayers can continue producing as a sack artist, then it might be able to snag him as a bargain pick. His relative lack of previous production and his age should keep his market price manageable.

Yet, his potential is good enough to earn Ayers a spot in our rankings.

8. Mario Williams, Defensive End

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If we were making this list a year ago, there's a good chance defensive end Mario Williams would be near the very top of it. The former N.C. State standout racked up 14.5 sacks with the Buffalo Bills and earned a first-team All-Pro selection in 2014.

If we fast-forward to this offseason, however, we have to knock Williams down a few pegs. He wasn't nearly as productive with the Bills in 2015—just 19 tackles and five sacks—and he's another year older. At 31 years of age, he may be looking at a closing window in terms of his productive peak.

However, there is always that chance that Williams can regain the form he exhibited just two seasons ago. This potential is going to earn him a lot of attention on the free-agent market and is why he retains a spot on our list.

At 6'6" and 292 pounds, Williams is a long, lean and athletic edge-rusher, and teams are always in the market for those. However, they will question the effort he showed on the field in 2015, which is another reason why he is lower on our list. Pete Prisco of CBS Sports recently explained how Williams looked on film:

"

Forget the ability. We know players who get older have their skills erode, and Williams is 31 and coming off his 10th season, but this was much more than that. In many of Williams' games, he appeared to have one of those wink-wink deals guys make in practice. I won't go hard if you don't. Let's just make it look good. It was sad to watch.

"

If Williams is willing to put forth the effort, he can still be a difference-maker. This is why he should draw heavy interest. However, his market will cool considerably if teams are convinced he is done trying altogether.

7. Terrance Knighton, Defensive Tackle

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Defensive tackle Terrance Knighton isn't going to wow anyone with his raw statistics, but as a run defender, he can be valuable.

He is hitting the market after playing on a one-year deal with the Washington Redskins in 2015. He finished the season with 29 tackles and 1.5 sacks. Pro Football Focus rated him 27th overall among defensive tackles for the year.

At 6'3" and 354 pounds, Knighton is a true space-eater in the middle of a defense, and his ability to clog running lanes isn't going to be measured in tackle production. Though the ability to stop the run is often overlooked, it is still an integral part of any NFL defense. This is why he is going to have value so long as he remains productive.

Redskins head coach Jay Gruden summed up Knighton's value perfectly last offseason.

"We were excited to get him," Gruden said, per Don Banks of SI.com. "He’s a unique guy because he’s such a wrecker in the run game. It’s just hard to find those guys. ‘Yeah, go ahead and run up the middle against him. Now it’s 2nd-and-8, so good job.’”

Though he will turn 30 before the start of the 2016 season, Knighton should have the ability to fill either a short-term or long-term need. This is exactly why he should be a valuable commodity on the open market.

6. Nick Fairley, Defensive Tackle

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Defensive tackle Nick Fairley was up-and-down during his four years with the Detroit Lions, which is why they were willing part with the former 13th overall pick last offseason.

Well, he went on to sign a one-year "prove it" deal with the then-St. Louis Rams, and what he did was prove that he can be a dominant front-line defender.

The 6'4" and 308-pounder didn't put up gaudy number with the Rams. In fact, he produced just 29 tackles and half a sack in 2015. However, he did appear in 15 games on a rotational basis and proved to be an outstanding contributor.

Pro Football Focus rated Fairley 11th overall among defensive tackles for the 2015 season.

Now back on the market, he should draw plenty of interest from teams that are looking for young, versatile players with upside. He recently turned 28 years old and has shown the ability to bring interior pressure on opposing quarterbacks.

Fairley produced 11.5 sacks between 2012 and 2013 in Detroit.

If teams believe Fairley can recapture some of that pass-rush ability, his stock in free agency could quickly go up. Regardless, he is young and talented enough to be viewed as a long-term building block.

5. Ian Williams, Defensive Tackle

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Defensive tackle Ian Williams might not have the star power of some of the edge-rushers on this list. However, his breakout season with the San Francisco 49ers in 2015 showed that he can be a dominant force in the middle of a defensive front.

This past season, Williams racked up a whopping 65 tackles to go with one sack and one forced fumble. That's a hefty tackle total for an interior defensive lineman. Pro Football Focus rated Williams ninth overall for the 2015 season.

Because true nose tackles are rare, Williams is going to have a lot of value on the open market. Without one, defensive alignments like the 3-4 will have a difficult time being effective. At 6'1" and 305 pounds, he is a compactly built, immovable rock in the middle of a defensive line.

In other words, he's perfect for the nose tackle position.

Williams is also one of the younger players to hit the market this offseason. He won't turn 27 years old until just before the start of the 2016 season, so he should be able to lock down a team's nose position for the foreseeable future.

This combination of youth, productivity and potential is why Williams earns a spot on our list.

4. Jason Pierre-Paul, Defensive End

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Defensive end Jason Pierre-Paul is a bit of a question mark because of last year's fireworks accident that severely injured his right hand. He played in eight games for the New York Giants last season but had to do so with a club covering the injured extremity.

This was an issue because it appeared the club often limited Pierre-Paul's ability to make open-field tackles. If this turns out to be a problem, the 6'5", 278-pound defender may find it impossible to ever be a factor against the ground game.

However, Pierre-Paul still has potential as a pass-rusher, which is why he owns a spot on our list. He only produced one sack in 2015, but he frequently put pressure on opposing passers. Pro Football Focus credited him with 34 quarterback hurries in his eight games and rated him 12th overall among 4-3 ends in pass rushing for the season.

The demand for capable NFL pass-rushers is always significantly higher than the supply, so Pierre-Paul is going to draw interest. He only recently turned 27 years old, so if he can return to form, he can potentially provide a new team with a long-term building block.

The question for potential employers will be whether they can live with Pierre-Paul as a situational pass-rush guy and a potential liability on running downs.

3. Jaye Howard, Defensive End

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We'll forgive you if you're not super familiar with defensive end Jaye Howard. The two-year starter has been mostly overshadowed by more prominent defenders on the Kansas City Chiefs defense such as Justin Houston and Tamba Hali.

However, the former fourth-round pick out of Florida has developed into a solid starting-caliber 3-4 end. This past season, he proved that he can be a disruptive force in his own right, racking up 57 tackles and 5.5 sacks. Pro Football Focus rated him 59th overall among 3-4 defensive ends for the season.

At 6'3" and 301 pounds, Howard is an ideal fit for a 3-4 front, though his size could allow him to kick inside in a different system. There should be plenty of teams looking to sign the 27-year-old, and it sounds like Howard will listen to all of them.

"I'm open to going anywhere," Howard said, per Adam Teicher of ESPN.com. "I think my versatility is going to be able to make me fit into any scheme. I would love to stay in Kansas City, but I'm hoping to go anywhere that's going to allow me to just continue my success."

Howard has the potential to be a defensive cornerstone for the long term, and he should have an opportunity to step into the limelight at his next stop.

2. Damon Harrison, Defensive Tackle

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Few things look as good on film or on the stat sheet as sacks. However, there is still a big need for run-stuffers in today's NFL, and few are better at answering the call than defensive tackle Damon Harrison.

He has been a defensive monster over the past three seasons with the New York Jets, but his 2015 campaign was incredible. He racked up an unbelievable 72 tackles to go with a half sack and a forced fumble. Harrison was the interior anchor for New York's 4-3 base defense and finished the season rated sixth overall among defensive tackles by Pro Football Focus.

Teams that are looking for a true nose tackle for virtually any alignment should be quick to target Harrison once the market opens on March 9. He has shown he can thrive in a 4-3 base, but at 6'4" and 350 pounds, he should also have the size to clog the middle of a 3-4 front.

At just 27 years old, he should also thrive in his future home for many more seasons.

Harrison isn't likely to make a whole lot of highlight reels in the coming years, but he can make whichever team lands him immediately better on defense. This is why he is our top-rated defensive tackle and the No. 2 lineman on today's list.

1. Malik Jackson, Defensive End

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Malik Jackson played primarily at the defensive end position in the Denver Broncos' 3-4 front in 2015. At 6'5" and 293 pounds, however, he has the size and build to fit at multiple positions depending on the system.

This potential versatility is one of the reasons why Jackson earns our top spot in the defensive linemen rankings. His youth—he just turned 26 in January—is another. Of course, the biggest reason is that he is quickly developing into a true impact defender.

Jackson racked up 45 tackles, five sacks, one safety and seven passes defended in 2015. Pro Football Focus rated him ninth overall among 3-4 ends for the season.

Oh yeah, and Jackson also just helped the Broncos win Super Bowl 50. That's definitely going to add a little polish to the resume.

A player of Jackson's caliber, of course, isn't going to come at a bargain price. According to Troy E. Renck of the Denver Post, the Tennessee product is looking for a deal in the $14 million-per-year range.

Jackson isn't going to come cheap, but whichever team lands him is going to get a defensive building block who can potentially be in place for a while. Jackson can play the run, cover pass-catchers and pressure opposing quarterbacks. The best part is that he can do all of it very well.