DETROIT -- Cornerback Terrion Arnold was still in disbelief a day after the Detroit Lions' shocking 45-31 divisional round loss to the Washington Commanders.

The Lions roared to a 15-2 regular season, securing home field throughout the playoffs as the No. 1 seed. But Arnold & Co. had seen a year filled with hope and high expectation end much sooner than anticipated, falling far short of their goal of reaching the franchise's first Super Bowl.

"The hardest part," Arnold said during end-of-season locker cleanup, "is just knowing, like, the room is gonna be different. Like even in the locker room after the game we took time to say, you know, 'Guys, really cherish this moment because it's gonna be different.' That's been the hardest thing about being in the NFL.

"Normally in college and stuff like that, you go back, and you normally see everybody, but the NFL is a business. People get better opportunities, which I know they'll take those. I'm happy that they'll take those, but it's hard because you get close to a person and then they leave you."

Indeed, things will look much different next season -- particularly among the coaching staff. This offseason, the Lions lost both coordinators and three other assistants. Former defensive coordinator Aaron Glenn is the new head coach of the New York Jets. Former offensive coordinator Ben Johnson went to Chicago as head coach. Along with him, Johnson brought receivers coach Antwaan Randle El and assistant QBs coach J.T. Barrett. In addition to losing Glenn from the defensive staff, former defensive line coach Terrell Williams was hired by the New England Patriots to be their defensive coordinator.

Despite the coaching changes, though, Lions general manager Brad Holmes cites head coach Dan Campbell and a roster brimming with young stars as reasons to believe Detroit's title window is not closing just yet.

"I think that we just stay the course and keep building like we've been. I do think that we're very close," Holmes said. "Obviously, I thought that we were very close this year, but nothing is going to alter what our approach has been in terms of trying to continue to improve and keep building."

FROM DAY 1, rookie running back Sione Vaki noticed the seriousness of this year's Lions team as it was preparing for a Super Bowl run.

"I was just sitting there, feeling the energy in the room," Vaki told ESPN of his first team meeting with Detroit. "It was just like, 'Damn, ain't no wasting time. You're here now. Get to work.'"

Although Lions All-Pro offensive tackle Penei Sewell would later question whether the pressure may have gotten to some of his teammates, Vaki couldn't sense any drop-off from any of the guys as they were in the thick of competition and rewriting the franchise's previous losing narrative.

"I don't know. These boys, like the whole team, we was making history, we was winning games and things like that. So, yeah, I would be fooled not to say that," Vaki said. "We thought that we was gonna go in there, handle our business [against the Commanders] and just play our game. Just do what we've been doing. So, I guess some of that could've got to our head, but nah, it's too many dawgs in here, but I don't know."

Detroit had five turnovers in the playoff loss to Washington, including four by quarterback Jared Goff (three interceptions and a fumble). The Lions entered the game with 15 players on injured reserve, and starting cornerback Amik Robertson was lost on the defense's second play after sustaining a broken arm.

Still, Campbell made no excuses for the swift playoff exit as he looked to the future.

"I told the team this, Just don't forget it," Campbell said. "Don't forget it. Look across the field at the end of that game. Somebody feels good and somebody doesn't, just remember that feeling,' No different than last year, that's all. I mean, those are the things that you etch in your mind that you don't ever want to forget.

"And I'm the type of person that replays every bad decision, every bad move in my head over and over on purpose just to let it burn and eat away at you, because that's the stuff that makes you not want to feel that anymore, is to go back for more. So, we fell short, it wasn't good enough, the players are extremely disappointed, I know the fans are, I certainly am, but we will reload, and we will be back."

IN LIGHT OF the high-profile departures on the coaching staff, the Lions brought back former senior offensive assistant John Morton, who was the Denver Broncos' pass coordinator the previous two seasons, to be the offensive coordinator. And Campbell maintained continuity on the defense by promoting linebackers coach Kelvin Sheppard to replace Glenn as the new defensive coordinator.

In Denver, Morton helped Broncos QB Bo Nix finish with the second-most passing touchdowns (29) by a rookie in NFL history. Nix's 3,775 passing yards were the eighth most by a rookie in NFL history.

Sheppard, 37, played in the NFL from 2011 to 2018 after being a third-round pick by the Buffalo Bills. He enters his fifth season on the Lions' coaching staff, beginning as the outside linebackers coach in 2021 and spending the last three seasons as the linebackers coach.

The Lions are also adding former NFL quarterback Bruce Gradkowski to their staff as an offensive assistant coach, a source told ESPN's Adam Schefter. Gradkowski -- who played 11 years in the NFL with the Buccaneers, Raiders, Bengals, Steelers and Browns -- spent the past two seasons as the offensive coordinator and playcaller of the St. Louis Battlehawks of the UFL.

"We're going to come back stronger, we're going to learn from this, and it's just more fuel on the fire, is what it is," Campbell said.

In anticipation of a move this offseason, Glenn had begun preparing Sheppard for a defensive coordinator role months before accepting the head coaching position with the Jets.

"I think he's damn near close, if not there, to be ready to do that," Glenn said on Dec. 12. "He's a damn good coach, he's fiery, everything that you need as a linebacker coach, he's that. And there are certain coaches on the staff that I think have to be bulldogs, and he's one of those coaches at that position, along with D-line, O-line and running back. You have to be a freaking bulldog, and he does a good job of that."

Replacing two top-notch coordinators is a big deal. But Holmes feels strongly that the success will continue to carry over even without them.

"I feel very confident in that just because that's the other thing with coordinators leaving and if there's tweaks to scheme and all of that. As long as Dan is the head coach here and as long as I'm here, those are things that we talk about that are not going to change," Holmes said.

"So, maybe a scheme tweak here and there, but if a player's going to come in here, he's a Detroit Lion or he's not. Same as that question about a coach coming here. I think Jared [Goff] in particular, that's something that I know is at the forefront of Dan's mind in terms of what's going to be the best thing for him. So, I have faith that everything will be OK."

THE LIONS HAVE more than $50 million in cap space as they enter the 2025 offseason.

Detroit has 31 pending free agents, but many of them are backups. Although Holmes expressed after the season that contract negotiations hadn't begun yet, the Lions will have to figure out what to do with defensive tackle Levi Onwuzurike, cornerback Carlton Davis III and guard Kevin Zeitler, who are all unrestricted free agents this offseason.

Davis was a pivotal piece of the Lions defense before suffering a season-ending jaw injury. He was acquired in an offseason trade with the Tampa Bay Buccaneers and finished with two interceptions, 11 passes defensed and 56 tackles while starting in all 13 of his appearances before being hurt in Week 15.

Zeitler signed a one-year deal with the Lions last offseason after a Pro Bowl year in Baltimore. In Detroit, he didn't miss a beat, starting in all his 16 appearances. But at 34 years old, it's hard to tell if Detroit is willing to offer him anything other than another short-term deal.

Onwuzurike experienced a bounce-back season after spinal fusion surgery for an injury that he originally suffered in 2022. He started 10 games while logging a career-best 13 quarterback hits with 28 total tackles and 1.5 sacks.

However, they'll have to balance out those veteran contracts with possible extensions for cornerstone players such as star edge rusher Aidan Hutchinson, 1,000-yard receiver Jameson Williams and All-Pro safety Kerby Joseph. All three are entering the final year of their rookie deals.

There is certainly a high level of interest in getting those players new contracts, notably Hutchinson and Joseph, who ended with a league-best nine interceptions.

The goal in Detroit is to keep their draft picks in house while reloading for a Super Bowl run next season. It might be a tall order with a remade coaching staff, but Holmes and Campbell have brought the franchise from afterthought to legitimate contender and see no reason the Lions can't stay there.

The players are committed to bringing that vision to life.

"I think this year we were able to display a lot of maturity," Lions defensive tackle Alim McNeill said. "We could always play ball. That's why everybody's in the NFL, they're all good football players. Everybody is. But once you can put other things on the field like your maturity and different things that you learn from vets before you, just being able to apply that to the field, I think we were able to do that this year and we did that in a lot of games this year, actually.

"It's just going to continue to grow for us. We still have a fairly young squad. We still have guys that are coming into their form so I for sure see a great future for us."