The Dallas Cowboys are making a massive roster move in the middle of training camp. The Cowboys and defensive tackle Quinnen Williams have agreed to terms on a three-year, $105.9 million contract extension, per reports from NFL Network's Ian Rapoport. Dallas acquired Williams in a midseason trade with the New York Jets last year. Now, he will be a member of the Cowboys for years to come and a cornerstone of the franchise's future plans on defense.Details of Quinnen Williams' Historic Contract Extension with CowboysDallas Cowboys defensive tackle Quinnen Williams (92) walks off the field with trainers after an injury during the second half against the Minnesota Vikings at AT&T Stadium. | IMAGN IMAGES via Reuters ConnectWilliams is now one of the highest-paid defensive linemen in league history. His new five-year, $153.15 million deal is the third-largest ever for his position.Additionally, the contract extension includes a record-setting number in guaranteed money for a defensive tackle. Williams earns $101 million total guaranteed and $63.35 million guaranteed at signing, per ESPN's Adam Schefter.Williams, 28, is a four-time Pro Bowler and is clearly viewed by Dallas as one of the best interior defenders in the NFL. In his first season with the Cowboys last year, he played in seven games (all starts) while posting 21 total tackles (nine solo), 1.5 sacks, three tackles for loss and one interception. But now, the expectations are reaching a new level. He will have to prove that the front office's confidence in him is worth it as the team looks to turn around its defense.This is a developing story and will be updated as more information becomes available. —Sign up for the Cowboys Daily Digest newsletterfor more free coverage from Dallas Cowboys on SI—Add us as a preferred source on GoogleFollow