GREEN BAY — Winston Moss thinks he knows what his linebackers are capable of. Even though they haven't necessarily shown it yet.

It's not so much that starters Nick Barnett, A.J. Hawk and Brady Poppinga — or backups Desmond Bishop, Abdul Hodge and Tracy White, for that matter — haven't been solid. But the starting threesome — plus free-agent signee Brandon Chillar, who'll compete with Poppinga on the strong side — must raise its game if the Green Bay Packers' defense is to become a championship-caliber outfit.

"They have to exceed potential. Exceed potential," said Moss, who serves as the Packers' assistant head coach in addition to linebackers coach. "I think if Nick Barnett exceeds what he can do in his overall game, if A.J. can do the same thing, Brady, Brandon, Bishop, Hodge, White — if all those guys exceed their potential, it's going to be unbelievable. That's all I can say."

Up to this point, the unit hasn't been unbelievable. While Barnett (165 tackles, 3.5 sacks, two interceptions, one fumble recovery) and Hawk (129 tackles, one sack, one interception, one forced fumble, one fumble recovery) were solid tacklers, neither made enough impact plays to please the Packers.

Both players expect more from themselves as well, and expect their production to spike now that they've played two seasons alongside each other.

"When we're on the field, we have to talk, because we're working so closely together. If you mic'ed both me and Nick up during a game, you'd hear us talking the whole time," Hawk said. "It's almost like when you're around people and you're talking about your job, you almost have a different little language. I know what he's going to do, he knows what I'm going to do.

Added Barnett: "You can't play in our scheme and not communicate. You have to be on the same page. But I think the vocabulary has really minimized now. We don't have to explain much. We can say one word, something maybe not even in the playbook, between each other and understand what's about to go down."

One of the few starting battles in all of camp will be between Chillar and Poppinga, whom the team values so much it signed him to a four-year contract extension worth a reported $17 million — even though he might not emerge as the starter at sam linebacker. Moss did say Poppinga will open camp with the No. 1 defense on Monday, while Chillar will work with the 2s.

"Sooner or later, we're going to take a look at Brandon with the 1s to see how he relates to Nick and A.J., the defensive line, and the communication he has with the safeties. Sooner or later, that's going to happen," Moss said. "Do I have a timeline on that? Have I written down exactly what kind of reps they're going to be taking? No. I don't have that. I think there's going to come a time when the pads get on and we see how it's going that my instincts will kick in and we'll say, 'Let's do it this way.'"

Chillar is better in coverage than Poppinga, but just because he was the Packers' lone free-agent signing doesn't mean he'll ultimately win the starting job. If he does, though, Poppinga would likely see more action in what the Packers call their "Frisco" package, which uses three down linemen and three linebackers in front of five defensive backs, unlike their usual nickel package (four down linemen with Hawk and Barnett).

"Brandon's going to come in here with the mentality that he wants the starting job. He's not coming here to be a backup guy," Moss said. "He's very poised in coverage. A strength of his is obviously covering the pass. So that's what he's going to bring to us. He's more of a finesse player as far as comparing him to Brady. He can play the run well, he just plays the pass better."

After that foursome, competition will be fierce for what figures to be only two remaining roster spots. Desmond Bishop is coming off a promising rookie year, while Abdul Hodge is finally healthy after two years of knee problems. The only issue is both players are middle linebackers by trade, and the team could have trouble finding room for both. There's also Tracy White, who's most valuable on special teams.

"It's going to be a (heck) of a deal, to find out who's going to end up as our linebackers," Moss said. "Because Abdul looks like a different guy. Tracy's been very, very strong in his backup role. And then Desmond Bishop has taken, as far as his competitive spirit, his attitude and his physical presence, a big step. He's truly developed.

"What those guys (Hodge and Bishop) have shown me this offseason, and what they've done so far, they're making a case for themselves that you're going to have to find a spot for both of them. Bishop has done an outstanding job, and Abdul has, too."