Most rookies and young players figure to make NFL 53-man rosters through their special teams prowess. Chicago Bears special teams coordinator Dave Toub has a list of young players he wants to see make an impact in Thursday's game against Denver.

"I want to see J.T. Thomas," Toub said. "He’s really establishing himself as a linebacker now. Now we want to see him do something on special teams."

Thomas missed last season on injured reserve after being drafted in the sixth round. He made news in the offseason by getting arrested on a misdemeanor possession of marijuana charge. 

With veterans Geno Hayes and Blake Costanzo likely to make the team, there could be one or two openings for young LBs like Thomas, Dom DeCicco, Patrick Trahan or Jabara Williams.

Toub will also get his first good look at nickel back D.J. Moore trying to play gunner on punt team.

"He’s got the quickest first step out of anybody on the team, so we think he’ll be able to get to the edge," Toub said. "It’s just a matter of him having the effort to go down every down and finish. It takes a lot of effort to play gunner because you’re going to get knocked down. It’s going to be brutal and you have to keep coming back."

Plans are to use rookie first-round pick Shea McClellin on KR and PR teams.

He'll look at rookie CB Greg McCoy as a KR and Dane Sanzenbacher and possibly rookie CB Isaiah Frey on returns.

Sick bay: WR Devin Hester joined LB Brian Urlacher in missing practice, but his absence was due to illness and not personal reasons, as was Urlacher's.  ... WR Eric Weem (ankle) sat out practice, as did LB Jabara Williams (hamstring) and DT DeMario Pressley (ankle).

Rush job: Former Illinois and Chicago Rush player Derek Walker signed a one-year contract and undrafted free agent rookie tackle Tyler Hendrickson was waived. Walker played part of this past season with the Chicago Arena Football League team after coming into the league in 2009 as an undrafted free agent and spending brief stints with Seattle and San Francisco.

It's practice, man: Practice was shortened Tuesday to two hours and players went without pads as it took on a lifeless, walk-through look in severe heat. The Bears have a practice scheduled for Wednesday that is closed to the public, and have now closed it to the media. 

No country for old men: Peyton Manning won't find the  Bears going easy on him because he's coming off a bad injury Thursday. "You don’t play the game to hurt anybody, at any time but it’s a physical football game," coach Lovie Smith said. "Our pass rushers want to get to the quarterback, whoever he is. I started with Peyton Manning his first year at Tennessee; we’ve known each other for a long time. I’m happy to see him back out there on the football field but we need to play well against them."

Follow Bears reporter Gene Chamberlain on Twitter @CBSSportsNFLCHI.