Aren't two of those rival games? Rival games are never easy and it's really not all that easy to drop a team the second time around. I can see the Bears dropping one of those games.
With how the Bears started the season, and this far into the season, they should not go worse than 13-3, and they swept the toughest "rival" opponent, Minnesota. I can't see how they lose to Detroit. Green Bay is a potential game they lose, but Lovie Smith made defeating the Packers their number one goal, getting into the playoffs is just "gravy". So if he fails in that respect, then I don't know what to say.