No. They're 8-4. He's been going on bad wheels for a while, and the Bears have been scraping by with the league's second-ranked defense.
Not to diminish what Urlacher means to this team, but it's easier for defenses to get by without their stars than offenses. You've seen it with Baltimore, playing without Terrell Suggs and Ray Lewis.
This is a turnover-based defense -- 17 interceptions, 11 forced fumbles. If you want to worry about losing an injured player, worry about Jennings and his eight picks. Goodnight, pally.