Put it this way....according to one of the playoff odds pages I was reading today, a Lions loss increases the Bears playoff odds by 17%. A Packers loss improves it only 5%
Guess it depends on how confident you are in the Bears winning tonight. A Lions loss would allow the Bears to still control their destiny going into week 17 (and eliminate Detroit) regardless of what the Bears do tonight. A Packers loss would mean nothing if the Bears also lose. If they win, the Bears would eliminate the Lions but would still need to beat the Packers (or a Lions loss) to make it
So if they flex the Bears-Packers to sunday night and the Bears lose tonight they could be eliminated before their week 17 game (being purposely over negative so that good things happen)