The New England Patriots had already taken some decisive hits at linebacker in the offseason, losing key contributors Kyle Van Noy and Jamie Collins Sr. in free agency, as well as captain Elandon Roberts. Then came the biggest hit of all, with Dont'a Hightower opting out of the 2020 season.

Like fans of the team, inside linebackers coach Jerod Mayo was jarred by the Hightower news.

"Initially, I was shocked, disappointed, a bunch of emotions went through my head," Mayo said.

But then he stepped back, learned more about why the decision was made (family considerations), and began to do what football coaches and players are trained to do: Plow forward.

"I totally respect the decision. From a football standpoint, you just have treat it like an injury. We've always had that 'next man up' mentality and that's how we're approaching it going forward," he said.

What stands out about the "next man up" philosophy for the Patriots linebackers, led by 2018 fifth-round pick Ja'Whaun Bentley, is youth. The Patriots haven't been this young at their off-the-ball linebacker spot since 2009, when Mayo was starting in his second NFL season alongside fellow second-year player Gary Guyton.

As Mayo himself noted, "Right now, it's crazy to say Bentley [who turns 24 this month] is one of the older guys in the room."

To quantify the turnover at linebacker, consider that Van Noy (766 snaps), Collins (765) and Hightower (684) played the third-, fourth- and fifth-most snaps on defense last season, reflecting their status as rare, multifaceted 'backers who play on every down. Only reigning NFL Defensive Player of the Year Stephon Gilmore (cornerback, 952) and longtime captain Devin McCourty (safety, 946) played more.

Bentley totaled 275 snaps and he's primed to see that number easily double this season. At 6-foot-2 and 255 pounds, he has the size to thump in the running game. The question is whether he's athletic enough in space to be effective in the passing game.

Part of the reason Bentley slipped to the fifth round of the draft was a lack of speed (4.85 seconds in the 40-yard dash), but his intangibles as the first three-year captain in Purdue history, along with his intelligence, made him a Patriots target despite his lack of an invitation to the NFL combine.

"If you were to look at last year and his production per play, he was very productive when he was out there," said Mayo, referencing Bentley's 39 tackles. "You think about the players we had in that room, it was a crowded room. I look forward to giving him more opportunities, and hopefully he's able to stay healthy and keep that production up."

Bentley had proven to be a quick study as a rookie, earning two starts in his first three career games before a torn biceps ended his season. He played 16 games last season, with two starts.

"We had a lot of great talent. Shout out to all those guys. Obviously you respect the decision that Hightower made," Bentley said. "We'll come in here, you have to work, guys have to figure out their roles, and we have to keep pushing forward."

That's the message to Michigan's Josh Uche (second round, No. 60), Alabama's Anfernee Jennings (third round, No. 87), Wyoming's Cassh Maluia (sixth round, No. 204) and Arkansas' De'Jon "Scoota" Harris (undrafted) -- all rookies who have a rare opportunity to carve out a role as an early off-the-line linebacker. Missouri's Terez Hall, an undrafted free agent from 2019, is also part of that mix after spending last season on the team's practice squad.

"One advantage of having a young group is that they are very moldable," Mayo said. "Right now, they come in and really don't know much. I've always liked that -- to have those young guys who are willing to try just about anything.

"Sometimes the older players kind of get stuck in their ways, especially players that have done something a certain way and at a high level -- you try to tweak that and it's a little bit more difficult. I'd say with the younger guys, they come in with a willing attitude ... you can work on technique things. They really haven't been coached at this level. I really look forward to the challenge and the opportunity."

Patriots outside linebackers coach Steve Belichick added: "We enjoy coaching all players -- veteran and young guys. There's a lot to teach these guys, a lot for them to learn, but we're doing the best we can bringing them along."

Good linebacker play has been a hallmark of the Patriots' Super Bowl championship teams, going back to the early 2000s with Tedy Bruschi, Bryan Cox, Roman Phifer, Ted Johnson, Mike Vrabel, Willie McGinest and Rosevelt Colvin, among others.

When the Patriots won their next trio of Super Bowls, the position was capably manned by the likes of Hightower, Mayo, Van Noy, Collins and Rob Ninkovich.

Now, it's a new era at linebacker, where the Patriots are as young and untested as they've ever been.