The Bills had great anticipation and hope before last Sunday's game against the Patriots. Those were dashed when the Bills' offense couldn't produce anything and Josh Allen got hurt. I respect the heck out of Buffalo's defense, but they are a deflated team this week and forced to go with journeyman backup QB Matt Barkley. Allen isn't accurate. Neither is Barkley. Allen was a running threat, however, and could make a big play. Barkley can't run, nor produce big plays. 
The Titans are a solid team that could be feared if Marcus Mariota is able to step up his game. Mariota showed signs of doing that last week. He has a 7-to-0 touchdown-to-interception ratio and his pass protection was the best it has been all season last Sunday against the Falcons. The Bills' defense is much more physical and superior to the Falcons. The Titans, though, get their best offensive lineman, left tackle Taylor Lewan, back from suspension. 
Tennessee has edges at all the skill positions as the Bills can't match Derrick Henry in the backfield, nor Corey Davis at wide receiver.