With an admission about his back, Brian Urlacher created doubt about the future of his Bears' career that the team cannot ignore as it plans ahead. Suddenly the contract extension that Urlacher and the team had begun exploring informally looks like a risky commitment to an aging middle linebacker with arthritis. The Bears still owe $22.4 million to Urlacher after this season, including a whopping $7.35 million salary in 2011 when he will be 33.