For whatever reason on pre-game shows, ESPN, etc. they always refer to the yardage leaders as #1 Defense, Offense, etc. While, it is true the Bills D may be #1 in yardage allowed, they are not really anywhere near that in points allowed. While yardage can be an indicator of a D's abilities, points win games. Limiting points seems to be the best stat to lead in if your are a Defense. My take anyway.
For what its worth, ESPN stats show the Bills D 19th in points allowed at 25.1 points per game. Tennessee is #1 giving up 16.8 ppg. If I had my choice I would give up yards all day to have the #1 scoring defense (especially considering our O's struggles).