Buffalo is receiving a 2018 sixth-round pick that can become a fifth-round pick based on performance, according to a source.
The trade will reunite Dareus with head coach Doug Marrone, who coached the Bills from 2013-14.
A two-time Pro Bowler, Dareus, 27, was the No. 3 overall pick in the 2011 draft. After averaging 7 sacks per season in his first four seasons, Dareus has only 6.5 sacks total in his past three.