Waiting as long as he did to get proper treatment has caused that much of a problem, and hopefully, if he sticks to his rehab, that will be the lager extent of it.
Of course, Urlacher is in a contract year, and every week he misses is another dollar sign floating away from his next payday. He's going to push hard to come back as soon as possible.
Adrian Peterson agitated to get on the field for a month, but the Vikings decided that the long-term impact was more important that the short-term gain (which would include getting him to be quiet about playing).
Unlike the Vikings, the Bears have realistic Super Bowl aspirations and will need Urlacher for the long haul. If he pushes too hard and comes back too soon because he is worried about that next contract, he could re-aggravate that injury and cost himself—and the team—his services for a longer period.
Of course, Urlacher does more than just tackle people. He leads the defense, calling out offensive schemes he sees, making adjustments and helping to disguise his defense's intentions.
Sure, Nick Roach or whoever else steps into his role can replace his physical production to some extent, but the mental aspect of the game is something only experience can teach, and frankly, a guy like Roach hasn't had the time or need to learn it.
The Bears need Urlacher for the push into the playoffs. I expect it to be a rough road this year, but one which will see his return to his usual level of play, provided he takes his time rehabbing and doesn't return before his body is ready.