There are unknowns about the Jaguars' defensive line.

There's the health of Terrance Knighton, of Tyson Alualu. There's the health of Aaron Kampman, and the fact that the veteran defensive end's immediate future may not be known until training camp.

There's a rookie defensive end, Andre Branch, being counted on to pressure quarterbacks, something that's possible but is still an uncertainty.

But those unknowns? They're not what the people around the defensive line talk about this offseason when discussing a unit that has been under as much scrutiny as any position group on the team in recent years.

They talk potential, and do so with a smile.

"We've got a chance, definitely," defensive end Jeremy Mincey said.

When Mincey says that, he doesn't just mean the line can be good. Good is expected.

"We're just focusing on sharpening our edges and continuing from last year and not taking any steps backwards," Knighton said. "The group started off young two to three years ago and we've got the same group and I feel like we only can get better."

What the Jaguars linemen believe they have a chance to be is the best they have been as a group since Joe Cullen took over as defensive line coach in 2010, a year removed from a disastrous 2009 season when the defense registered a league-low 14 sacks.

Since then, improvement has come in increments:

Twenty-six sacks in 2010. Thirty-one this past season.

That's the right direction, certainly, but they're not numbers that satisfy Cullen or the rest of the line, a group that emphasizes pass rush to the extent they call themselves rushmen rather than defensive linemen.

This year, Cullen said there are a couple of reasons the line's goal of ascending to elite status is attainable. One is that most of the core group – Alualu, Knighton, tackle C.J. Mosley, end Austen Lane, Mincey and Kampman – has been with Cullen since 2009.

 "They know what we want, how we want to do it," Cullen said. "I want my guys not only to know how to do it, but why. Then, they can do it better."

The other reason: depth.

Cullen said even with some of the uncertainties, this line will be the deepest it has been in his three seasons. At tackle, Alualu and Knighton are the clear starters, but he said he also considers Mosley – who signed a long-term extension earlier this off-season – a starter. D'Anthony Smith, a third-round selection in 2010, is healthy and participating in the off-season after missing two seasons with injuries, and 2012 seventh-round selection Jeris Pendleton has potential to be in the rotation as a run-stuffer.

At end, the team re-signed Mincey to a long-term extension after a career-high eight sacks last season, and while Lane appears likely to enter training camp as the starter, the team likes what it has seen from Branch. Kampman, who has played in just 11 games since signing as a free agent in the 2010 off-season, hasn't practiced full speed in the off-season, but he has looked healthy working on the side and could make an impact if available.

"Unquestionably, this has the potential to be the best group since I've been here – potentially," Cullen said. "We want to play at a high pace for four quarters. You need to rotate guys and have seven or eight men in a constant rotation.

"By no means are we a finished product. We've all got to get healthy, and we have to blend at the right time and hit our groove at the right time, which they will. I really believe they will."

Cullen said as OTAs closed last week he told the group he wished all of them could make the roster – not out of sentiment or loyalty, but because for the first time since his arrival, all of the players in camp are NFL caliber.

"Collectively, the bottom end of the defensive line is going to be as good as it has been," he said. ""I think each and every one of them has a place in the league. There will be competition for the final roster spots."

Depth in the NFL is obviously good, but at defensive line it is more. It is critical, and without it, the most talented "front four" can be limited in effectiveness. In reality, who starts on the defensive line can be less important than who plays on third down.

"The money downs, third downs, those are going to be earned," Cullen said. "It will be the best four rushers, who's producing. There's going to be competition for those four spots."

If those four have yet to be determined, Mincey said that's OK, because Mincey said that's the case with the defensive line overall. Mincey has played with good lines with the Jaguars and lines that have struggled. This line, he says, has a chance to be on a par with the best.

"We can get there," he said. "We can definitely be better. No question in my mind, we can be better. It's going to take some work, it's going to take a lot of work, but we can be there."

But it's work that once completed can eliminate a lot of uncertainty – and result in a line of a caliber that hasn't been seen around the Jaguars in a while.