I know this is all rumor and speculation, but what in the draft isn't? Word going around is that the St. Louis is interested in picking BYU QB John Beck who on many boards is ranked as the 7th or 8th best QB, but has been rising up the board. The problem is some think Detroit might take him with their 2nd round pick, so they need to get in front of Detroit and are looking to move into a later first round pick.
If I pull out our handy draft value chart I see that they have the #52 and 82 picks which combine for a number of 560, which happens to be real close to the Bears 600 valued 31st pick. The result of the deal would look like this for the Bears.