Records show that Williams' 2016 base salary has been reduced from $6 million to $4.25 million. There were no other changes to Williams' deal, suggesting Williams took a pay cut instead of the team restructuring the $1.75 million difference into incentives or a bonus.
Williams' agent, Pat Dye, did not immediately respond to a request for comment. The Bills do not publicly discuss terms of player contracts.
Williams' cap number has dropped from $8 million to $6.25 million, while the Bills' cap space has increased from $5.82 million to $7.57 million, according to NFLPA records. Of that amount, the Bills will need to reserve space to reach deals with their draft picks this summer.
Williams, who turns 33 in June, missed the final 10 games of last season with a knee injury that eventually required surgery. He expressed a desire in November to continue his playing career.
The Bills' longest-tenured current player, Williams was drafted by Buffalo in 2006 and made Pro Bowls in 2010, 2012, 2013 and 2014. He signed a one-year extension last spring, through the 2017 season, that bumped his pay in 2015 and 2016.