HENDERSON, Nev. -- The first time Jon Gruden met Cory Littleton, the jewel of the Las Vegas Raiders' first free-agent class?

Try some four months after Littleton signed his three-year, $36 million deal with $22 million guaranteed to rebuild the Raiders' linebacker corps.

"When he walked in in his uniform, with a helmet on," the Raiders coach said, referencing training camp. "The first day."

The pandemic has made for scary times in the real world. And some strange times in the world of the NFL, what with no hands-on offseason program to speak of and virtually all offseason work being done, well, virtually.

But this much is true -- the Raiders' addition of Littleton, a tackling and coverage machine and one-time Pro Bowler for the Los Angeles Rams, is no mere stopgap measure; it signals a culture shift and an absolute overhaul to a unit that has struggled mightily in pass coverage for a long time.

Per ESPN Stats and Information and NFL Next Gen Stats, Raiders linebackers ranked 18^th in the NFL in allowing a completion percentage of 74.1% when they were targeted as the nearest defender in coverage last season (the NFL average was 73.7%).

They also ranked 26^th in yards per target (8.4), 31^st in TDs allowed (9, only the Arizona Cardinals were worse with 12) and were tied for the second-fewest interceptions (1, with the Kansas City Chiefs not getting a single pick in such situations).

Besides bringing in Littleton, who can cover sideline to sideline, the Raiders also inked Nick Kwiatkoski from the Chicago Bears to wear the green dot as the defensive signal caller, traded for Raekwon McMillan from the Miami Dolphins after breaking camp, drafted Tanner Muse in the third round from Clemson and have been impressed with undrafted rookie Javin White from UNLV.

Only Nicholas Morrow, Justin Phillips and Kyle Wilber have experience as linebackers in defensive coordinator Paul Guenther's scheme.

"It looks like day and night, truthfully," said Raiders safety Johnathan Abram, when asked how different the linebackers look this season. "We've gotten faster on every single position on offense and defense but the linebacker corps does stick out."

Abram continued his scouting report, saying Morrow has put on weight "but is still flying around," while calling Kwiatkoski "The General. He's calling the defense like he's been in it from the start with PG [Guenther]."

Playing with Littleton, Abram said, was like playing with another safety because "he rotates off of me and E [Erik Harris] and Damarious [Randall], whoever's in the game. And he can run and cover all of the tight ends just as well as we can. So, I mean, it's just a totally different [linebacker] corps. An entire different unit. The defense looks way faster and way better."

And it all starts with Littleton.

Last year, he was targeted on 16.3% of his coverage snaps, the seventh-highest such rate among linebackers with 250 coverage snaps, per ESPN Stats and Information. He had a 'Ball Hawk' rate -- the percentage of targets as the nearest defender which resulted in a pass defensed or an interception -- of 13.0%, which ranked 15^th of 50 linebackers with at least 250 coverage snaps.

Also, Littleton had 13 'Hustle Stops,' where the player covers 20-plus yards of in-play distance from snap to tackle to make a successful play based on the yards to go by down, last season, fifth-most among linebackers. As a unit, the Raiders linebackers had 18 'Hustle Stops' last season. Combined.

Not bad for a guy who entered the NFL as an undrafted rookie in 2016 and played a lot of defensive end at Washington.

"Basically, my mindset coming into the league was find where my value was," Littleton said. "Before, playing in college, my value was being a defensive end -- pass rusher mostly. Coming into the league, I knew there was going to have to be some type of transition and me having to play linebacker. So, all the aspects that came with linebacker I just try to be the best one I can be."

The 6-foot-3, 228-pound Littleton is far from the prototypical thumping linebacker of NFL lore. Rather, he represents the evolution of the position.

And he's already been on a team that went from woebegone to winner. Witness the Rams going from 4-12 in 2016 to 13-3 and the Super Bowl two years later.

Pssst, the Raiders were (checks notes) 4-12 two years ago.

"It just comes down to a want-to," Littleton said. "And me coming here, I see the same type of hunger that we had when we were in L.A., coming off of losing seasons and wanting to be better because you know that you can. And everybody is here motivated to doing just that."

First up in the season opener on Sept. 13 are the Carolina Panthers, who are rebuilding but return All-Pro running back Christian McCaffrey, who rushed for 1,387 yards and 15 TDs last year while catching 116 passes for 1,005 yards and four scores.

The Panthers also have a familiar face in linebacker Tahir Whitehead, who spent the past two years with the Raiders and was praised by Gruden on Wednesday.

"He made a lot of tackles," Gruden said of Whitehead. "He took a lot of criticism but I really think he was a good sideline-to-sideline player."

Alas ...

"We love Kwiatkoski, what he brings to our team -- his ability to find the ball and get us lined up, in and out of good defenses, is a real ingredient that we need," Gruden added. "And Littleton, as you know, is an underneath coverage linebacker who is exceptional. And we're going to need that against McCaffrey, and [New Orleans Saints RB Alvin] Kamara and some of these beasts that we're going to see in our division.

"So, it's good. Nick Morrow has improved and we think the addition of McMillan will give us some depth and versatility that is something that, obviously, we feel we need."