Not only do the Patriots and Bills have the two best statistical defenses in the NFL, but there is a strong weather factor, too. Throw in this being a huge division game with two top-notch defensive coaches and you have all the right ingredients for an Under. 

New England is first in scoring defense holding foes to 15.8 points a game. Buffalo is next giving up 16.5 points. The Bills rank No. 1 in total defense. 
The weather forecast is frightful - rain, gusty winds in the 20-40 mph range and cold weather. In other words, Buffalo in December. 

Mac Jones hasn't experienced this type of weather. Bill Belichick is sure to have a sound defensive game plan for Josh Allen, who isn't having the big year he had last season. The Patriots are second in takeaways.