For as long as John Fox has been in Carolina, the Panthers have run a variation of the Tampa 2.  Fox's defenses traditionally keep the safeties in zone coverage, and focus on getting pressure from the defensive front.  In that model the Panthers have been fortunate to line up players like Julius Peppers, Kris Jenkins, and Mike Rucker over the years.  

But times have changed.  As the line aged and personnel turned over it lost effectiveness in the technique-oriented schemes of Mike Trgovac.

Ron Meeks runs the same sets, but his emphasis is less on technique and misdirection and more on burst and quick reactions.  After a slow start in 2009, the Panthers responded very well down the stretch and the defense developed into one of the league's best.

The Panthers have a lot of talent on the defensive side of the ball, which helps, but it's still not focused on the line.  That's not to say the line is a weakness, it isn't.  But it's not one of the league's best by any measure.  It can be improved, the only question is whether it can be improved on enough to be worth the effort.

Whether an improvement is worth the effort is usually tied to what kind of effort is required.  This article is all about the line, both what we have and what's out there. In that, maybe the level of effort can be determined.  In this story, we look at who we have, and at who we can get without giving up a player or picks.

Carolina doesn't do anything fancy on it's line, its a standard under front in the 4-3 set.  That means two Defensive Ends who can apply pressure from the edge, an Under Tackle to line up in the three-technique spot and generate pressure on the interior, and a two-gap run-stuffing Nose Tackle to occupy the Center and a Guard. 

Big, strong, run-stopping DEs who excel in a 3-4, where they play closer to the interior, won't really contribute much as Ends in our scheme, at least not from a pressure perspective.  They don't have the tools we look for on the edge. 

The same thing can be seen when lining up a light Under Tackle at the Nose Tackle spot.  If that player can't occupy both the Center and the Guard, then Jon Beason will have to shrug off the block of an offensive lineman rather than the fullback, and instead of the Panthers surrendering one or two yards on the ground, the opponents gain three or four.

Right now, the Panthers have three defensive ends under contract.  They normally like to carry four or five on the roster, with at least one being a "tweener" - someone who can move inside to the tackle position on obvious passing downs.  Barring injury, all of these players should be considered front runners to make the final roster.

• Everette Brown (6'1", 256 lbs.)  Brown is a 22 year old playmaker with a great mix of moves and an explosive burst off the edge.  His game is all about pressure, and after watching his rookie campaign it looks a lot like he'll register a lot of sacks over the course of his career.  He has a tremendous motor and a wealth of athleticism, but he doesn't have the ideal size you look for in an NFL pass-rusher. He also needs to improve against the run.
• Charles Johnson (6'2", 275 lbs.)  In three NFL seasons, the 23 year old Johnson has developed into a well-rounded Defensive End.  He has good quickness and power, although he's somewhat lacking in raw speed.  What separates him from the pack is his knack for getting penetration.  He's got top instincts, and does a great job reading plays and anticipating where the ball is going.  He's also very good at playing on the interior as a one-gap Defensive Tackle.  If he continues to improve, it will be hard to keep him on the bench.
• Hilee Taylor (6'2", 250 lbs).  Taylor is 23 years old and will be in his third season.  He has a lightning-fast first step and good quickness.  He's on the roster in part because he's a very hard worker, and has shown the ability to learn.  But at the same time, he's small and doesn't have great speed in pursuit.  He also doesn't do well against the run.  He's got potential, and he could continue to develop and eventually be a strong backup, but that's the most you can expect of him.

Then you have the Free Agents.  The first thing that jumps out at you is how shallow the class is.  There just aren't a lot of players out there worth signing.  The second is the average age.  All of the Ends and almost all of the Tackles are in their 30s.

The Panthers have two Unrestricted Free Agents on their roster, Julius Peppers and Tyler Brayton.  It's almost a certainty they'll re-sign Brayton, he wants to be a Panther and they like what he brings.  The Peppers situation is another story altogether.

• Tyler Brayton (6'6", 280 lbs.) Brayton is still going strong at 30.  He plays an intelligent game, and brings a lot of intensity to the field.  He's got a little burst, but not enough to reliably get him into the backfield, and he lacks a lot of pass rushing moves in general.  He has speed though, and makes plays in pursuit.  He's better against the run than the pass, but his tall frame allows him to bat down passes.  He's versatile, and routinely slides inside on passing downs.  He'll probably hold on to his starting job for at least another year.
• Julius Peppers (30 years old, 6'7", 283 lbs.). Pepp is well known to Carolina fans, having played his first eight years for the Panthers.  Love him or hate him, he's the best available on the UFA Market.  He'll command a multi-year deal in the neighborhood of $15 million per year with somewhere around 50 million in guaranteed money.  The alternative is to franchise him, locking him up for one year at $21 million.  His profile has been done to death by fans and sportswriters, and there's no reason to drag it out here.

Then there are the Defensive Ends from other teams that may be available.

• Richard Seymour (6'6", 310 lbs.) Oakland Raider Seymour is getting older at 30, and may have lost some of the power he needs to be effective as a Defensive End in a 3-4, but he still has a lot to offer to a 4-3 defense, where he could play at either End or Tackle.  He's got great size and strength, and a nice mix of power moves and technique.  He's lost a little of his burst off the line, but he still moves well and can make plays in pursuit.  He'll command a large contract, and it's not likely that the Raiders will let him get away, considering what they traded to acquire him in the first place.
• Aaron Kampman (6'4", 260 lbs.) Kampman struggled in his move to OLB in Green Bay's new 3-4 defense.  At 30, he no longer has elite speed in pursuit and just isn't as effective in space as he needs to be.  But the two-time pro-bowler has sound technique, plays with a lot of discipline, and has the moves you look for to get through the line and into the quarterback's face.  He may not have too much left, but he would be an effective one or two-year starter on most rosters.
• Marques Douglas (6'2", 290 lbs) Douglas is a 32 year old 3-4 DE for the Jets with at least a year or two left.  He's quick, athletic, and has good strength.  But he's never produced much on the field and doesn't rush the passer well.  He's better suited for the 3-4, where he can use his strength to contain the run, than he would be as a pass-rushing end in the 4-3.
• Jarvis Green (6'3", 285 lbs.) Green is another 3-4 DE on the market.  He's a good athlete with a quick first step and respectable speed.  But he's got one or two basic moves to get to the quarteback and has been mistake-prone in the past.  At best, he's a 31 year old Hilee Taylor, and probably wouldn't make it out of Training Camp.
• Jason Taylor (6'6", 255 lbs.) At 35, Taylor's best years are behind him.  He still has a great first step and a quick burst off the line.  He also has multiple moves to get to the quarterback. He's not particularly strong, but he's good at identifying screends and stretching a play until help can arrive.  But he's slowing down, and probably has too much of an eye on his career off the field to have much more of one on it.
• Adewale Ogunleye (6'4", 260 lbs.) The Chicago product is 32 now, and his best pass rushing days are behind him.  He's still a good athlete and he has multiple moves to shed blockers and penetrate.  He's also got decent speed and is good in pursuit.  But he gets pushed around a lot in the running game and wears down late.
• Kyle Vanden Bosch (6'4", 278 lbs)  The Titan DE is a real high motor guy in the Brayton mold, but at 31 he's older and has already shown signs of wearing down.  At best, he would be a good defender against the run, but he can't get to the quarterback, and is probably better suited for a 3-4 defense at this point.

So there you have the Defensive Ends, current and available.  The Panthers will have at least four, the three currently on the roster and Tyler Brayton.  While they would like to have Peppers as well, at $21 million the price may be too steep.  If Peppers isn't around, they might look at Kampman or Ogunleye, but those are about the only realistic options Free Agency allows.

The Draft has some intriguing prospects that may be available when they finally pick, like Greg Hardy or Carlos Dunlap, but the Panthers may have a bigger need at Receiver, and there really isn't a rookie out there who looks capable of coming in and contributing at a high level right away.

At Defensive Tackle, the Panthers have an interesting mix of players.  The Panthers got caught with their pants down in Training Camp last year when starting tackle Ma'ake Kemoeatu was injured.  They quickly discovered that they had no depth at the Nose Tackle positon.  When coupled with the rest of the defensive struggles to adapt to Ron Meeks' system, Carolina proved to be very vulnerable against the run.

Marty Hurney took a while to find a solution, but he landed Louis Leonard from Cleveland.  Then Leonard got injured.  So he went out and signed Hollis Thomas, and the line was finally able to operate as designed.  Down the stretch, the Panthers played at a very high level, enough to finish at a respectable 8th in the league.  How high a level?  In their first eight games the Panthers gave up 24.5 points per game.  In their final eight that number plunged to 14.

The Panthers may not bring Thomas back, but you can bet they'll start Training Camp with more than one option at Nose Tackle.  Not only will Kemo return, but they have Leonard and former Chief Tank Tyler as well. 

Here's a look at who they currently have on the roster, starting with the Nose Tackles.

• Ma'ake Kemoeatu (6'5". 345 lbs.)  Kemo is 31, and the first thing you think about him is that he's just a huge player.  He's got good mobility though, and is intense at the point of attack.  He easily occupies two blockers.  But he's not particularly athletic and doesn't rush the passer well.  He also suffered an injury to his achilles tendon, which is hard for a big body to recover from.
• Hollis Thomas (6'0", 340 lbs) Thomas is 36 years old, and although he's short, he's wide and powerful.  He's very stout against the run, but doesn't consistently rush the passer well.  When both are healthy and at the top of their game, Thomas is probably a little better than Kemo.  But Thomas is not known for his conditioning, and until last year he had developed a reputation for being injury prone.  Given his age, he'll likely be cut before camp.
• Louis Leonard (6'4", 325 lbs) The former Brown represents the Panthers future at the Nose Tackle position.  At 25, he's just coming into his own as a solid run stopper.  He has the size you want in a Nose Tackle, but he also has some explosion and quickness, and he's an intense player.  If he continues to improve as he has since coming into the league as an undrafted free agent (like Kemo and Thomas), he could develop into a very good starter.
• Tank Tyler (6'2", 306 lbs.)  If Leonard doesn't work out, the 24 year old aptly-named Tank should.  The former Wolfpacker has the size and power you want in a run stuffer, but he's also got a lot of quickness that you don't generally associate with a Defensive Tackle.  He's faced questions about his work ethic, and hasn't been consistent in the NFL yet.  But the Panthers have some good line coaches, and if he responds he has the potential to make Kansas City look stupid for giving up on him.  At the very least, he provides high quality depth.
• Damione Lewis (6'2", 301 lbs.)  At the Under Tackle position, the Panthers will once again start with the 31 year old Lewis.  He's is quick, explosive, knows how to shoot the gaps, and runs well.  But as he ages, he's more prone to being steered around by opposing guards, and isn't the threat in pass coverage he once was.  His best days are clearly behind him.
• Corvey Irvin (6'3", 302 lbs)  The 24 year old is the likely future at the Under Tackle position.  He spent his rookie campaign on injured reserve, but not before he impressed the coaching staff with his athleticism and quickness.  He's got a good work ethic, and is versatile enough to be equally effective against both the pass and the run.  Unfortunately, he doesn't yet have a lot of technique, and he's already proven to be injury prone.  With coaching, he has a lot of upside.  But he won't be starter-quality this year.
• Nick Hayden (6'4", 292 lbs) is also 24, but he has a lot more polish on his game than Irvin.  He's big and strong and quicker than you'd think.  But he's still got some work to do as a pass rusher, and he's not suited to play the nose.  Last year he lost 20 pounds before the season in anticipation of playing in Ron Meeks' defense, one which valued speed and quickness more than bulk and technique.  Then he earned the emnity of fans when he was asked to replace Kemoeatu.  Hayden's not really a Nose Tackle, and he had pushed his weight in the wrong direction for that role.  He was terrible at it, but late in the season when he got his opportunities in the Under Tackle role he played very well.  He outplayed Lewis against New England, and showed signs that he could not only be a quality backup, he might develop into a legitimate starter.
• Derek Landri (6'2", 290 lbs)  Where Nick Hayden dropped weight to start the season, the 26 year old Landri added weight in Jacksonville to try and hold on to a starting DE spot when they moved to the 3-4 defense.  The experiment didn't work out for him, and he was released late in the season for lack of production.  When he's in the right position though, he's more than capable of delivering quality minutes.  Landri has a nice intensity, and gets a good burst through the line on the snap.  He can collapse the pocket while picking up runners along the way.  He's not the most athletic tackle on the roster, and needs to improve his technique, but in the Panthers' system he might do very well once he drops the weight back off.
• Ed Johnson (6'2", 296 lbs.)  Finally, the Panthers have signed 26 year old Ed Johnson to the roster.  Johnson was released by the Colts for a lack of production, in a system very similar to what Ron Meeks is running in Carolina.  It's not likely that Johnson will make it through Training Camp.

The Free Agent pickings at Defensive Tackle are even worse than they are for Defensive End.  Interestingly enough, all three of the UFA DTs out there play the Nose position, which is where the Panthers were hurting in 2009.  With that said though, a Defensive End in the 3-4 can usually be effective as an Under Tackle in the 4-3, so there are options there if the Panthers are seeking an upgrade.

• Casey Hampton (6'1", 325 lbs) is 32 and on the downside of his career.  But he's a great Nose Tackle, he takes up a lot of space and consistently demands a double team to get him out of the hole.  He doesn't have a lot of burst, but he plays with a lot of power and is able to collapse a pocket.  He's also not likely to get out of Pittsburgh.
• Ryan Pickett (6'2", 340 lbs.) is coming off a very good first season as a Nose Tackle in the Packers' 3-4.  The 30 year old is quick, powerful, and mobile.  He's a good penetrator and he tackles well.  But he doesn't have the strongest work ethic and can wear down.  Late in games he has a tendency to let blockers get under his pads.  As with Hampton, he'll likely remain with his current team.
• Vince Wilfork (6'2", 325 lbs.)  The 28 year old Wilfork is the cream of the UFA DT crop this eyar.  He's an outstanding run-stuffer, with a wide body that demands a double team.  He plays hard every down, has a nice burst, and can give a pass rush from the nose.  He's also a smart player with a good work ethic, but he's battled weight issues and wears down late in games.

The Draft offers some very nice depth at the Defensive Tackle position this year.  The top five could all go in the first round, and there's a lot of quality after them.  This may not be a huge need, but some nice talent could be available on the second day, talent that could develop into an eventual starter.

Obviously, a lot of what Hurney needs to do depends on the Peppers situation and how it plays out.  If Peppers is franchised and returns, then the Panthers will likely stand pat on the line in both Free Agency and the draft.  If he's released, then look for them to court a free agent and further address the Defensive End position in the draft.  In that scenario, they may also look at taking a stab at another Defensive Tackle, to provide additional pass rushing help.  The final scenario has Peppers franchised and traded.  If that happens, everything will depend on what they get in return.

Regardless, the Panthers will find themselves in decent shape along the line in 2010.  They may not have the best line in the league, but what they have now is plenty good, even without Peppers.  And when you put players like Thomas Davis and Jon Beason behind any line, it looks that much better.