Norton, 51, has served as the Raiders defensive coordinator since 2015.
The Oakland Raiders have fired defensive coordinator Ken Norton Jr., the team announced Tuesday.
Since their 2-0 start to the season, the Raiders have lost six of their last eight games after a 33-8 loss to the New England Patriots in Mexico City on Sunday.
"After careful thought, I have made a difficult decision to part ways with Ken Norton, Jr. as defensive coordinator," coach Jack Del Rio said in a statement. "I have the utmost respect for Ken as a person and as a coach, but I feel that moving John Pagano into the play-calling role will best utilize his wealth of experience. I appreciate Ken's passion and commitment to the Raiders since coming aboard and wish him the best going forward."
Oakland has allowed 24.7 points and 367 yards per game on the season ranking 21st and 26th in the league, respectively, showing zero improvement from last season, when the team ranked 20th in points allowed and 26th in yards allowed.
The Raiders defense has zero interceptions on the season and are tied for last with the Giants with just 14 sacks. Opponents have been particularly successful in the air, as Oakland is at the bottom of the league in opponent completion percentage and passer rating. Opposing quarterbacks have averaged a 113.3 passer rating against the Raiders.
Norton, a three-time Pro-Bowler and three-time Super Bowl champion, was a linebacker for the Dallas Cowboys and San Francisco 49ers from 1988-2000. The 51-year-old previously served as a linebackers coach for USC and the Seattle Seahawks before joining the Raiders.
Norton will be replaced by assistant head coach John Pagano, who joined the Raiders this season. Pagano served as the defensive coordinator for the then-San Diego Chargers from 2012-16 and coached within the Chargers organization since 2002. John is the brother of Indianapolis Colts head coach Chuck Pagano.
Although many saw the move as long overdue, Raiders outside linebacker Bruce Irvin expressed his disappointment with the move on Twitter, calling it "bulls---."
Oakland (4-6) remains in the hunt for the playoffs in a weak AFC. Jack Del Rio's team will face division rivals Denver on Sunday before taking on the lowly Giants the following week.