Buffalo have lost five of their last eight games to fall to 6-6 – three games behind Miami in the AFC East.
The Bills rebounded from an opening-night defeat with three straight wins, but they have struggled for form since the 25-20 defeat to Jacksonville in London.
They edged New York a week later 14-9, and then had to rebound from a 29-25 defeat at New England with a 24-18 victory over Tampa Bay.
Buffalo failed to build on that victory though, as they lost 24-18 in Cincinnati and 24-22 at home to Denver.
The Bills avoided a third straight loss as they blew out the New York Jets, 32-6, but they again failed to string together wins as they blew a late lead to lose 37-34 in overtime in Philadelphia.