Those 4 teams are:
-Seahawks-49ers-Chargers-Vikings
He has been an amazing player during his tenure in Chicago. He was regarded as one of the best run-stopping interior defensive linemen in all of football. He also has been an amazing leader for the Bears and seeing him leave the organization would be a tough blow.
However, Hicks had some injury-related problems in the last 3 years. It looks like age might be getting the best of him at this point. This isn't to say that he is done, but it seems that his best days are behind him.