Knox, who recently underwent hand surgery, has been ruled out for Sunday's game against the Dolphins.
The Bills are holding out hope that Knox will miss one or two games, as he hasn't been placed on injured reserve following a Week 7 bye. Tommy Sweeney looks set to serve as the Bills' top pass-catching tight end against Miami, but Buffalo is expected to sign a free agent or promote another player from the practice squad to provide depth Week 8.