When a knee injury ended linebacker Nick Barnett's 2008 season back in November, the Packers' defense benefited considerably from the versatility of Brandon Chillar and Desmond Bishop, linebackers who could play multiple spots.

With the change to the new 3-4 defensive scheme, that may be the case again in 2009.

Chillar and Bishop both have been mentioned by Head Coach Mike McCarthy as possible contributors both at inside and outside linebacker in the 3-4, and while on the surface one might think a player would prefer to have a specific spot to learn and play, neither Chillar nor Bishop expressed reservation about potentially being switched back and forth as the defense makes the transition.

"Throughout my career I started at every position in the 4-3, the 'Will', 'Mike', and 'Sam', so being able to make that switch and transition between positions on a week-to-week basis helps," said Chillar, who played both the weak-side (Will) and strong-side (Sam) spots last season, his first in Green Bay after four years in St. Louis. "It's going to be a lot of learning, but I'm ready for it."

So is Bishop, who initially filled in for Barnett in the middle after his injury last season and then played more on the weak side when A.J. Hawk shifted to the middle.

"To play more than one position and be more versatile is more credibility for myself," Bishop said. "I'm definitely looking forward to playing everything I can. That's kind of my role, to play wherever they need to plug me in at, to be available and be ready to go."

The potential for multiple duties is a bit taxing during the current offseason program, as Chillar and Bishop try to learn both the inside and outside linebacker spots in the 3-4, which are very different. Inside linebackers are primarily run-stoppers who may have to take on blocks from offensive guards, while outside linebackers might do everything from rush the passer to cover a tight end or running back in the passing game.

While most of the team's linebackers have been slotted for certain positions - Barnett and Hawk are considered pure inside guys, while Brady Poppinga, Aaron Kampman and Jeremy Thompson, among others, are seen on the outside - the versatility of Chillar and Bishop could help the team in several ways.

First, Barnett is coming back from reconstructive knee surgery, and while all indications are his rehab is going well, the defense is still nearly four months away from suiting up in full pads for the first time in training camp. The start of camp will be just short of nine months since Barnett's injury (Nov. 9), a fence line of sorts as to whether or not he'll be completely ready, so having reinforcements inside is a wise approach.

Second, with all of the sub-packages that go into building a 3-4, players who can handle multiple duties simply give defensive coordinator Dom Capers more options on different downs and in different situations.

But before all the X's and O's execution comes the mental part, and that's where Chillar and Bishop have had to focus some energy during the first month of the offseason program, in addition to their regular strength and conditioning work.

"The defense is all new terminology, and not only do you need to know the formations as the offense gets ready, but once they start shifting and motioning, that's where the intricacies of it come in," Chillar said. "When they shift a running back out or put a receiver in motion, all that stuff, you can have a new call. But basically it's terminology."

Chillar said he played a touch of 3-4 during his days with the Rams, while Bishop said in college at Cal his team had one defensive package with a 3-4 alignment. But otherwise, it's all new, though the good thing is there's plenty of time between now and the end of July to study and ask questions.

"I like learning," Bishop said. "I'm kind of embracing a new challenge, so to speak. I want to learn the defense. It's had some success throughout the league, and I'm excited to get into it and make it work."

Chillar and Bishop both had some big moments for the Packers in the old scheme. The more established veteran of the two, Chillar was more consistent, becoming Green Bay's best linebacker defending the tight end in the passing game, a role that was key in two of the biggest wins of last season, against Indianapolis and Chicago at home. Chillar led the linebackers by defending nine passes, and he added 13 special teams tackles, including five in the first two weeks when that was his primary duty.

Meanwhile Bishop had more dramatic moments, both good and bad. Upon replacing Barnett in Minnesota right after the injury, he allowed Chester Taylor to elude him for a 47-yard catch-and-run for a score, but he came back that same game to stuff Adrian Peterson on fourth-and-1, causing a key turnover on downs in the fourth quarter.

Then four weeks later against Houston, Bishop was having his best game as a pro when he started on the weak side in Chillar's place. He had a career-best 12 tackles, with two forced fumbles and his first career sack. But on the Texans' final drive, he lost track of tight end Owen Daniels, whose 27-yard reception in the final minute set up the game-winning field goal.

"You just (have) amnesia to the bad plays, you forget about them," Bishop said of his approach to the new season. "You learn from them and try not to repeat them again. It's a football game. You're going to make some good plays, you're going to make some bad ones, but as long as you make more good plays than bad, you should be all right. So I'm just looking forward to making more good plays and getting an opportunity to do that."

{sportsad300}Whether more of those opportunities will come from an inside linebacker spot or an outside one may not be determined for either player until well into training camp. And then there's always special teams, to which both have proven they can contribute. Bishop has 27 special teams tackles in his first two seasons in the NFL.

"I'm just an athlete, so I can play the outside, rush off the edge, or cover tight," Bishop said. "Whatever it is, I think I pretty much can do it. I'm ready to take on more responsibility, and if not, if my role is special teams, I'm going to embrace it and be the best player I can be in that area."

That's the best attitude to take, not only to handle the mild uncertainty that exists now but to prove one's value to the coaching staff over the long term.

"Whether it's defense or special teams, first and second down, third down, I've already been through it all last year," Chillar said.

"It's a new staff, and you have to trust them, trust their judgment, and then basically wherever they put you on the field, just play well. That's what I've always thought. Even when I was on special teams, wherever I'm at, I'm going to try to show out."