Manuel, the 16th overall selection and first quarterback taken in the 2013 draft, would have been due a $11.357 million salary in 2017 if the team had exercised the option. That salary would have been guaranteed in case of injury until the beginning of the 2017 league year in March, at which point it would have become fully guaranteed.
With the Bills declining Manuel's fifth-year option, the fourth-year quarterback will be due a fully guaranteed $2.827 million base salary this season before he becomes a free agent next spring.
Manuel served as the Bills' backup quarterback last season, behind Tyrod Taylor, who enters the final season of his contract as the Bills' undisputed starter. Manuel started in place of an injured Taylor for two games in October and lost both contests.
The Bills drafted former Ohio State quarterback Cardale Jones in the fourth round of the 2016 draft.
Manuel has not been the Bills' full-time starting quarterback since Week 4 of the 2014 season. After beginning that season with a 2-2 record and an 80.3 quarterback rating, Manuel was benched in favor of veteran Kyle Orton.
The Bills traded down from No. 8 to No. 16 in the first round of the 2013 draft and selected Manuel, who became Buffalo's starter as a rookie after a season-ending concussion to veteran Kevin Kolb in the preseason.
Manuel started 10 games as a rookie and missed six contests because of knee injuries. He compiled a 4-6 record in 2013 while passing for 11 touchdowns, nine interceptions and a 77.7 quarterback rating.