A Bears defense without Urlacher

8/31/2012 - NFL Chicago Bears
Brian Urlacher is the heart and soul of the Chicago Bears' defense. AP Photo/Nam Y. Huh

Much intrigue has surrounded Brian Urlacher and his left knee issues in the past few weeks. What kind of medical procedures did he undergo? Did he and the Chicago Bears know about this problem for a while and choose to cover it up? Why wasn't this injury addressed immediately after the 2011 season?

Although those are all interesting questions, the most relevant question is: What if this is a more serious injury than everybody thinks?

After all, Urlacher is a 34-year-old veteran linebacker who has absorbed a lot of hits in his storied career. When he broke his wrist in the first game of the 2009 season, the Bears' defense wasn't the same. And there doesn't seem to be any heir apparent at the position on the roster.

Urlacher has admitted that this knee issue likely will last all season and he will have to modify his practice participation during the week, which means there will be a lot of days he won't run the first-team defense. He vows to be ready for the Bears' season opener on Sept. 9, but that might be overly optimistic.

There is real cause for concern here. If Urlacher does miss some game time, what kind of an impact will it have on the Bears' defense?