A lot has to go right defensively and on special teams for a total of less than 40 to go Under in today's NFL with so many rules skewed to offense.

Justin Fields has been a disaster - so far. But this will be his sixth start. He has the legs and receiving talent with Allen Robinson, Darnell Mooney and Cole Kmet to put up his share of points. The Bears have gone Under in their last six games, but they've never had a total of less than 40 this season.

The 49ers have enough firepower to help this total get Over, too, especially since the Bears will be missing their best defensive player, star pass rusher Khalil Mack. He's out with a foot injury.

Chicago ranks 23rd in run defense. The 49ers are ground-oriented. Jimmy Garoppolo is playing for his job. So he knows he has to come in with a good performance here.