BBAO: Cause for concern with Urlacher?

We're Black and Blue All Over:

Here's what we know: Chicago Bears linebacker Brian Urlacher suffered what initially looked like a catastrophic left knee injury in the 2011 season finale against the Minnesota Vikings. The injury was later announced as sprained medial collateral and posterior collateral ligaments, requiring no surgery.

Urlacher didn't participate in the team's on-field work during the offseason, and when he resumed practicing at the start of training camp, he was wearing a brace on the knee. Now Urlacher has missed four consecutive days because of soreness in the knee, and it's possible he won't play in the Bears' preseason opener against the Denver Broncos.

Here's what we don't know: Are the Bears merely being cautious with a veteran who really doesn't need every practice repetition in camp? Or is this an indication that Urlacher hasn't fully recovered from the original injury and could be limited when the regular season begins?

Coach Lovie Smith didn't seem concerned when speaking with reporters Sunday, and in the short term the Bears can move outside linebacker Nick Roach to Urlacher's spot in the middle. But the Bears don't have anything close to an heir apparent on their roster, as they found out when Urlacher dislocated his wrist and missed 15 games in 2009. Their defense is much different when he is not on the field.

Continuing around the NFC North: