Mark Duffner got the call before anyone knew much for certain.

This was early last week, before Mike Mularkey interviewed for the Jaguars' head coaching job. Mularkey wanted to know if Duffner would agree to remain as linebackers coach if Mularkey indeed got the position.

Duffner said he would, and Mularkey did.

Duffner, the Jaguars' linebackers coach since 2006, officially signed to remain with the franchise early this week, and he said Tuesday morning he was thankful for Mularkey's offer, and glad to have the opportunity.

And not just because it meant not having to move.

"We really worked hard for a while to get this defense back to the successful level that it's had in the past," Duffner said Tuesday. "To reach that, and experience that this year, was a great thing. It was a fun thing.

"If we can continue and improve on that this year with the defense and the entire team – anytime you're part of something that's moving in the right direction, that's a lot of fun."

Duffner's and Mularkey's relationship dates to Duffner's days as the Cincinnati Bengals' defensive coordinator from 2001-2002, when Mularkey was the offensive coordinator of the Pittsburgh Steelers. Duffner said the two also had spent time together at various NFL Coaching Symposiums.

"He called me the night before he was going to meet with (Jaguars General Manager) Gene (Smith) about this job and told me, 'I'd like you to stay if I'm fortunate enough to get this thing,' " Duffner said. "I like what I've known and observed from him and feel very excited to have a chance to work for him."

Mularkey not only retained Duffner from the previous coaching staff, he also announced last week he is retaining defensive coordinator Mel Tucker – who served the last five games as interim coach – as assistant head coach/defensive coordinator and Joe Cullen as defensive line coach.

"We have a good defensive staff," Duffner said. "I enjoy working with Mel and Joe, and I enjoy our players – all the players on this team. I think we've assembled a quality group of people, offensively and defensively. To leave that wasn't something I was necessarily excited to do.

"I'm very excited to return and continue the efforts."

Duffner said although the Jaguars improved their defensive ranking from No. 28 in 2010 to No. 6 this past season, and although the linebackers consistently had played well during his tenure, he knew following the end of the season there were no guarantees.

"It's a wait and see," Duffner said. "You're very hopeful that whoever is making decisions on putting together a coaching staff recognizes the efforts you put forth, but there was uncertainty, certainly, because our contracts were not renewed.

"There was a certain level of concern, but you also have to have faith in what you do and hope that there's a bit of luck involved, too."

Of maintaining staff continuity defensively, Duffner said, "I think that's real important."

"From a scheme and structure standpoint on defense, we're kind of excited that we were able to have some returned success on defense," he said. "It's something we have put a lot of time and effort into and we're excited about that continuing and getting better. You have to work to do that. It's awfully competitive in the league, but it's like a piece of pizza. You take a bite and you want a little more.

"We've gotten back to having a level of success on defense and we want to keep that going."

As Duffner spoke, his office shelves and walls were bare, with boxes still packed on the floor – evidence of the time between the end of the season and last week not knowing his NFL future.

"A lot of people refer to the NFL as, 'Not For Long,''' Duffner said. "I'm not a big fan of that, but it is a fact of life. It's a performance-driven business. You establish a level of confidence based on the energy,effort, the work that you do, and you hope it's good enough that somebody catches it and wants you as part of their staff."

The Jaguars this past season got solid play throughout the season from the linebacker position.

Not only did middle linebacker Paul Posluszny sign as an unrestricted free agent and record the second-most tackles in franchise history (192), outside linebacker Daryl Smith once again was one of the NFL's most-consistent, most-productive players at his position.

Smith, an eight-year year veteran, set a franchise record with 15 tackles for losses this past season. On the other side, outside linebacker Clint Session registered 30 tackles, a sack and a forced fumble despite missing seven games with injuries. Veteran Russell Allen started six games in Session's place, and registered 31 tackles and a half a sack.

It's a group Duffner said has a chance to continue developing into perhaps the best group he ever has coached, and a group he said he very much didn't want to leave.

"I genuinely love these guys I have an opportunity to work with," Duffner said. "Aside from the fact that they're pretty darned good players, they're outstanding people. If I left, that would be the thing that would be difficult. The player-coach relationship is important to any objective you have, and to have left these guys – had it occurred – would have been difficult. I'm a believer in those things – the relationships and the development of those things – around the organization.

"Any time you invest of yourself – time and energy and effort – into something, and you see it start to take the form you want it to, you don't want to leave it. You don't want to turn it over to someone else.

"That's exciting, and very important. I'm pleased to have the opportunity to continue that."