Here are four things to know about new Patriots defensive coordinator Terrell Williams. Read more on Boston.com.

Terrell Williams, who Dan Campbell has described as the NFL's best defensive line coach, has left the Lions to become the DC in New England.

Detroit Lions defensive line coach Terrell Williams is departing the organization and will accept the defensive coordinator position with the New England Patriots. Williams had previously worked with Patriots head coach Mike Vrabel during their stint with the Tennessee Titans.