HENDERSON, Nev. -- Cory Littleton was supposed to be the crown jewel of the Las Vegas Raiders' 2020 free-agent class. Instead, the versatile linebacker, whose sideline-to-sideline coverage skills had been lauded, looked lost most of the season and admitted that he wasn't comfortable in the scheme until, oh, about mid-December.

Some nine months after signing that three-year, $35.25 million deal and ignominiously joining Miles Burris and Tahir Whitehead as the only Raiders linebackers in the past 10 years to play at least 600 snaps in a season and fail to record a sack, an interception, a forced fumble or a recovered fumble, per Associated Press.

Ouch.

Then there's safety Johnathan Abram, the third of the Raiders' three 2019 first-round draft picks who essentially played as a rookie this past season after missing all but one half in 2019 due to a shoulder injury. An oft-wayward heat-seeking missile, Abram's coverage skills left a lot to be desired, even if his temperament and athleticism check the boxes to be an intimidating presence.

Or did you miss Abram getting up and running 60-plus yards after being tackled to celebrate his second interception of the season by doing the 'Dirty Bird' dance in the Atlanta Falcons' end zone ... with the Raiders trailing 6-0 en route to being routed 43-6?

Yikes.

And, of course, there's defensive tackle Maliek Collins -- hailed as the "key" to the Raiders' defense by coach Jon Gruden in training camp before turning in zero sacks and zero tackles for a loss in 12 games. Then again, his $6 million free-agent contract was just for one year, so he's no sure bet to return.

Meh.

Introducing, then, Gus Bradley, the new Raiders defensive coordinator who, in a previous football life, was the architect of the Seattle Seahawks' infamous Legion of Boom. So how, exactly, can he fix what ailed the Raiders' defense last season?

"He's a great teacher, very passionate," Gruden told ESPN.com about Bradley, who got his first NFL job as a defensive quality control coach on Gruden's Tampa Bay Buccaneers staff in 2006 before being promoted to linebackers coach a year later. Bradley became the Seahawks' defensive coordinator in 2009.

"Love the way his defenses compete and the way he uses his personnel."

Fair enough, but how will that translate in Las Vegas for Bradley, who left Seattle to become the Jacksonville Jaguars head coach in 2013 before joining the Los Angeles Chargers as their defensive coordinator in 2017?

Details, Raiders players and fans need details.

And is he the guy to mend Littleton, Abram and, well, everyone else on defense for the Raiders? Especially in a division with the defending champion Kansas City Chiefs, who are riding their explosive offense to a second straight Super Bowl appearance?

"The basis is a lot of Cover 3, but I think it's evolved since Seattle," Bradley said. "When we went to Jacksonville, there's things we incorporated and when we went to the Chargers, too. So, I think it's more multiple than maybe the Seattle days. But it really revolves around looking at the personnel that we have and then putting guys in position where they can make a lot of plays. Position them to where they have the ability to make plays. So, that's a task that we'll look at in the next month or so -- really evaluate our personnel.

"Obviously, I'm familiar with some of the guys, but I think to be true to everybody, to really sit down and watch film before we talk really candidly about each player, is important."

No, Bradley did not want to go down the Raiders' roster, player by player, in his introductory virtual media conference. Not with so much in flux.

Bradley is bringing with him from the Chargers linebackers coach Richard Smith -- a former defensive coordinator with the Miami Dolphins (2005), Houston Texans (2006-08) and Falcons (2015-16) -- and defensive backs coach Ron Milus, who has been in the AFC West the past decade with the Denver Broncos (2011-12) and Chargers (2013-20).

Rod Marinelli, who replaced the fired Paul Guenther as interim defensive coordinator in Week 15, will be retained as defensive line coach, as will assistant defensive line coach Travis Smith (former DB coach Jim O'Neil was hired as the defensive coordinator at Northwestern).

Bradley, though, felt more comfortable talking about how his scheme fits the personnel at his disposal, rather than the other way around.

"When it all started -- a little bit of history when we were at Seattle -- there's some of us that came up and went into a room and kind of designed it," he said. "There's always things that are copied, but the foundation of the defense, really when it was brought to our attention, 'Hey, try to design something that allows young players to come in and play early.' It's not a defense that you're going to come to us and say, 'I'm going to need this 12-year veteran, I need this 13-year veteran because they're the ones that understand the system.' It was not brought up in that fashion.

"We knew we had to design something that players could learn and understand and maybe it was simplified for them and makes it hard on offenses. That was the whole idea behind it ... that's why you saw Earl Thomas come in and play early. Kam Chancellor, Richard Sherman, Bobby Wagner, these were young players that played early. It is a big part of it."

Abram, a founding member of LOB 2.0 in Sin City, with Littleton flying around ? Yeah, Raiders fans would like the sound of that, but again, the devil is in the details.

"Just like anything, there's defenses you have to have to be multiple," Bradley said. "You can't sit in one thing or two things the whole time and allow offenses just to tee off. There's some things to it, but I think really what's heavy on it is the fundamental part of it. That's the detail part of it."