The team and the agent of Cox have been negotiating the deal, which caused the big man to skip the last month of organized team activities. He reported to the team's complex just one week ago.
The 25-year-old was a first-round pick in the 2012 draft, and went to his first Pro Bowl this past season, after recording a career-high 9.5 sacks. He lead the team with 24 tackles for a loss or no gain, and has 22 sacks and six fumble recoveries during his four years in the league.
He has spent the last few seasons as a defensive end, but sources close to the team expect him to return to the defensive tackle position. After this long contract, he looks to find more success at the same position that got him in the NFL.