Veteran Hunter Hillenmeyer will start in Urlacher's place against the Cardinals.
Urlacher did work out and run sprints for the Bears training staff on a side field on Thursday.
"Brian Urlacher is getting better, but he won't play this week," coach Lovie Smith said.
At this point, playing Urlacher in the preseason might not be worth the risk, given the fact he's already well-versed in the defensive scheme, not to mention his high value to the unit. Teams usually play their starters for only one series in the preseason finale.
So there's a chance Urlacher won't see action again until the opener.
Michael C. Wright covers the Bears for ESPNChicago.com. ESPNChicago.com's Jeff Dickerson contributed information to this story.
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