If, as expected, strong-side linebacker Hunter Hillenmeyer is unable to play Sunday, he will be replaced by Nick Roach, a second-year player from Northwestern. Jamar Williams is also expected to get some snaps in that spot.
Hillenmeyer, who had thumb surgery last week but is practicing on a limited basis with a padded cast, has started 56 games since cracking the starting lineup in 2004, but Roach and Williams have already taken some snaps in his place this season. Both backups have played well, which is why the Bears don't expect to miss a beat against the Lions.
"We'll (just) be with another player, and when Hunter's healthy, and he comes back, we'll be back with Hunter," weak-side linebacker Lance Briggs said. "This is football. You plug in the guys that can play when (other) guys are unable to play. There's not a whole lot of difference. The next 'backer that's in, he's a lot darker than Hunter.
"He's a smart guy, comes from Northwestern. He moves well, he's really fast, he's a guy who you can put out against most guys in the league, and he'll be able to cover them. He picks everything up pretty fast. He's a guy that if he makes a mistake, he'll tell the coach what his mistake is before the coach can get it out of his mouth."
Told of Briggs' assessment, Roach said: "Whatever he said, I'll just double that up and say thanks."
Told that Briggs also said he was darker than Hillenmeyer, Roach said, "That's also true."
Taking advantage: The Bears are tied with the undefeated Titans, who they play next Sunday, for the NFL lead in takeaways with 16.
As the defense sees it, that takes some of the sting out of their No. 29 ranking in passing yards allowed.
"Turnovers are one of the biggest things in football," said nose tackle Dusty Dvoracek, who is tied for third in the NFL with 5 tackles for loss. "They're game-changing plays that turn around seasons. Turnovers are what you strive for - it's what this defense has been built upon since Coach (Lovie) Smith has been here."
Since Smith became coach in 2004, the Bears lead the NFL with 36 returns for touchdowns, including 12 on fumble recoveries and 6 on interceptions.
Keeping cool: In the wake of former Bears Hall of Fame linebacker Mike Singletary's postgame rant and halftime antics in his first game as a head coach of the 49ers, quarterback Kyle Orton was asked how Bears coach Lovie Smith demonstrates his anger.
"I don't think he's been too angry with me," Orton said, "so I don't really know."
Injury update: Cornerbacks Charles Tillman (shoulder) and Nate Vasher (wrist) and wide receiver Marty Booker all practiced without limitations Thursday. Defensive tackle Tommie Harris (knee), linebacker Hunter Hillenmeyer (thumb), wide receiver Brandon Lloyd (knee), safety Danieal Manning (hamstring) and punter Brad Maynard (rest) were all limited at practice. Harris and Maynard are expected to play. Of the other three, Lloyd might have the best chance to play but all are expected to be questionable at best.