Many have tried and failed, but it’s up to Gus Bradley to solve the long-standing defensive issues of the Raiders.

Bradley was hired by coach Jon Gruden Tuesday as the new Raiders defensive coordinator, the Bay Area News Group has learned. The Raiders confirmed Bradley’s addition to the staff.

The defensive coordinator for the Los Angeles Chargers for the last three years, Bradley succeeds interim coordinator Rod Marinelli, who took over when Paul Guenther was fired with three games remaining in the 2020 season.

Guenther was Gruden’s hand-picked choice as defensive coordinator when he returned to coaching in 2018.  The Raiders were at the bottom of NFL defensive rankings all season, with Gruden firing Guenther after a 44-27 loss to the Indianapolis Colts when both teams were playoff contenders.

Bradley and former Seattle defensive coordinator Kris Richard were the only known candidates to be interviewed.

It’s up to Bradley to upgrade a Raiders defense that has been poor for the better part of the last quarter century with only a few exceptions. Marinelli is expected to remain on staff as defensive line coach.

Bradley, 50, got his first NFL job on Jon Gruden’s staff with the Tampa Bay Buccaneers in 2006 as a quality control coach under Monte Kiffin. Bradley had served as the defensive coordinator at North Dakota State.

He moved up to linebackers coach but lost his job when Gruden and the staff were swept out a month after a 31-24 loss to the Raiders to close out the 2008 season.

On Kiffin’s recommendation, Bradley got an interview with first-year Seattle coach Jim Mora, who was impressed enough to hire him as defensive coordinator.

“Monte says, `J.L., listen to me, I have got a guy here in Tampa that is one of, if not, the finest football coaches I have ever worked with,” Mora told the Seattle Post-Ingelligencer. “He’s an A-plus. He’s a once-in-a-lifetime coach. You need to talk to him.”

Although Bradley had no experience as an NFL coordinator, Mora hired him. When he was fired after one season, Bradley retained the position under Pete Carroll.

With the Seahawks from 2009-12, Bradley, under Carroll’s guidance, molded a defense that included young talent such as Kam Chancellor, Richard Sherman, Earl Thomas, K.J. Wright and Bobby Wagner. Seattle led the NFL in scoring defense (15.3 points per game) in 2012 and went from 7-9 to 11-5.

Bradley was then spent four seasons as the head coach with Jacksonville, going 14-48, before being fired. He then joined Anthony Lynn as the Chargers defensive coordinator.

Chargers cornerback Casey Hayward told the USA Today at the Pro Bowl in 2017 Bradley came with a big thumbs up from Sherman.

“He just said, `Man, you are going to love this guy! You are going to be willing to run through a wall for him because that’s the type of person he is,” Hayward said. “That got me excited. He said he is a really good mix for a cornerback because he will mix things up. He’ll play some (cover) three, he’ll play some man. He said Gus will mix things up and bring different pressures.”

There are myriad ways to statistically rank a defense, with two of the most basic points allowed and yards allowed.

The Raiders were 30th in points allowed in 2020 and haven’t been under No. 20 since 2006, when they were No. 18. They’ve pretty consistently ranked in the 20s in terms of yardage, with the outlier being a No. 11 ranking under John Marshall in 2010.

The 2006 year was a statistical fluke in that the Raiders, besides being 18th in points allowed, ranked No. 3 in yardage. That season, under Art Shell, the Raiders were so poor on offense that opponents realized once the lead got to 10 points, the game was essentially over and they spent more killing the clock than trying to score.

Only twice in the last 30 years have the Raiders had a top 10 defense in terms of yardage and points. They were ninth in points and eighth in yardage in 1996 under the late Fred Whittingham but finished 7-9 in large part due to injuries sustained by quarterback Jeff Hostetler.

The other time was 1990, when under Dave Adolph the Raiders were No. 7 in points and No. 4 in yardage. They were 12-4 that season and defensive personnel included Greg Townsend, Howie Long, Jerry Robinson and Terry McDaniel.

Bradley has the following players under contract for 2021, ranked by salary cp number: linebacker Cory Littleton ($13.7 million), slot corner Lamarcus Joyner ($11.2 million), defensive end Carl Nassib ($9.5 million), defensive end Clelin Ferrell ($8.5 million), linebacker Nick Kwiatkoski ($7 million).

Other young players under their draft-pick contracts who will likely be foundation pieces for 2021 include safety Johnathan Abram ($3.1 million), cornerback Damon Arnette ($3 million), cornerback Trayvon Mullen ($1.9 million) and defensive end Maxx Crosby ($1 million).

The Raiders have spent much more freely on offense than on defense since Gruden arrived and as it stands players under contract account for $115.5 million under the salary cap with $70.6 allotted for defense according to overthecap.com.

Over the last two seasons, the Raiders made some significant defensive signings in free agent, most notably Joyner, Littleton and Nassib, but none made the kind of impact Gruden and Mayock had hoped.