Urlacher, who turns 36 Saturday, played 182 regular-season games for the Bears, totaling a team record 1,353 tackles and 41.5 sacks.
"After spending a lot time this spring thinking about my NFL future, I have made the decision to retire," Urlacher said Wednesday. "Although I could continue playing, I'm not sure I would bring a level of performance or passion that's up to my standards. When considering this, along with the fact that I could retire after 13-year career wearing only one jersey for such a storied franchise, my decision became pretty clear.
"I want to thank all the people in my life that have help me along the way," Urlacher continued. "I will miss my teammates, my coaches, and the great Bears fans. I'm proud to say that I gave all of you everything I had every time I took the field. I will miss the great game, but I leave with no regrets."
Urlacher, from Lovington, N.M., played collegiately at New Mexico and was the ninth overall selection in the 2000 draft by Chicago. In addition to five All-Pro and eight Pro Bowl selections, Urlacher was the NFL Defensive Player of the Year in 2005.
"Over the last 13 years Brian Urlacher has been an outstanding player, teammate, leader and face of our franchise," Bears Chairman George H. McCaskey said in March after the team had announced that it was unable to reach a contract agreement with Urlacher.
"As Bears fans, we have been lucky to have such a humble superstar represent our city. He embodies the same characteristics displayed by the Bears all-time greats who played before him and he will eventually join many of them in the Pro Football Hall of Fame. "
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