By Dan Durkin-

(CBS) Linebacker Shea McClellin (hand) won’t practice this week and has already been ruled out for Sunday’s game against the Packers, Chicago coach Marc Trestman said. His status is week-to-week.

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The status of center Roberto Garza (ankle) and guard Matt Slauson (ankle) is unclear, but they may be close to returning to the practice field.

“Right now I would say they’re day-to-day,” Trestman said. “I’m not optimistic, quite frankly. But it is possible they could be ready to go on Thursday and Friday at practice. But it’s day-to-day, and we’ll stay with the injury report on that.”

The Bears didn’t practice Wednesday afternoon but did have a walkthrough. Here’s the rest of Wednesday’s injury report, reflecting participation if there was practice.

Did not participate
— DE Jared Allen (illness)
— FB Tony Fiammetta (hamstring)
— WR Brandon Marshall (ankle)
— CB Sherrick McManis (quad)
— DT Jeremiah Ratliff (concussion)

Limited participation
— S Chris Conte (shoulder)
— S Ryan Mundy (shoulder)

Briggs on Bostic’s development

Linebackers Lance Briggs and Jon Bostic were on the field for every defensive snap Monday night against the Jets. With McClellin unavailable, Bostic had to slide over to the Sam linebacker in the Bears’ base package and was extremely active, leading the team with 13 tackles (six solos). Briggs has enjoyed watching Bostic’s development.

“Jon’s a smart man,” Briggs said. “He’s a student of the game. He’s a guy that studies his opponent very well. He goes into games with a lot of tips, formation alerts. Motion alerts and things they do on different downs. He’ll call things out.”

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Briggs also finds teachable moments on the field to pass on some veteran savvy, to help Bostic not tip the defense’s hand.

“Sometimes he’ll call it out too soon,” Briggs said. “Sometimes he’ll make a close call, too soon, and I have to say, ‘Jon, let me make the call.’  But he’s an eager guy. He’s smart. He wants to be a playmaker, and he is.”

Bears preparing for Peppers’ best shot

Sunday will be the first opportunity for the Bears to square off against their former teammate Julius Peppers, who has made the transition from a hand-on-the-ground defensive end in a 4-3 to a standup linebacker in the Packers’ 3-4 defense. Packers coach Mike McCarthy had high praise for the former Bear.

“We were excited about the opportunity to sign him,” McCarthy said. “He’s been an excellent fit for us. Our younger guys really look up to him. He has an excellent football mind schematically and how he fits into our system.”

McCarthy noted that while Peppers wasn’t asked to drop into coverage often in Chicago, he’s effective in that role.

“I know he played defensive end in Chicago, but in their fire-zone packages, you’d see him drop,” McCarthy said. “He does more of it now, but it’s a versatile scheme and he enjoys it.”

Briggs figures Peppers will be amped up against his former team and added it will be strange to see him in a Packers uniform.

“Julius usually has really big games against his former teams,” Briggs said. “I can remember playing against Carolina, the games we played against Carolina and stuff. But you know, it’s going to be tough to see Julius in green and yellow.”

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Dan Durkin covers the Bears for CBSChicago.com and is a frequent contributor to 670 The Score. Follow him on Twitter at @djdurkin.