JACKSONVILLE, Fla. -- The Jacksonville Jaguars (5-11) have much to fix after an embarrassing and disappointing 2018 season.

Find a quarterback. Make some cuts for salary-cap reasons. Re-work the tight end, running back and wide receiver positions. Get three key offensive linemen healthy in time for the 2019 season. Those are the major items on a long list.

If coach Doug Marrone is unable to repair the culture inside the locker room, however, all of those other issues might be irrelevant. The Jaguars have a serious culture problem.

They're undisciplined, unable to handle adversity and unaccountable. They fought out in the open and behind closed doors. One player threatened a reporter on social media. Another left the bench to get into a fight during a game. Another refused to go into a game. And in a very public display of insubordination, two players sat alone on the bench, disinterested in what was happening during the final game of the season -- which so angered executive vice president of football operations Tom Coughlin that he released an unsolicited statement after the game.

Jaguars coach Doug Marrone has hinted that he'll rule with a heavier hand in 2019, beginning in the offseason. Brett Carlsen/Getty Images

Those are just the incidents that have come to light. There are undoubtedly other issues only those inside the organization are aware of that contributed to a locker room crisis. The good news is that Marrone recognizes the problem and is putting together a plan to solve it -- because he believes he is to blame.

"It's the foundation [that has to change] and where I have made mistakes and there were cracks in it," Marrone said. "You see things that happened on the field, you know that you've spoken about it and it just doesn't resonate for whatever reason. I have always put that on myself. For me, you know the message that you want to deliver, but you better make sure ... I have to do a better job of how I deliver it to make sure that it resonates, and that's how you build the culture.

"You have to be able to communicate. It's the most important thing to get jobs done, and I obviously didn't do a good job communicating."

Marrone said the solution begins in April, when the players return for the offseason conditioning program. That's when warning signs of an impending issue began last season. Cornerback Jalen Ramsey skipped the 10 organized team activities to train with his father in Nashville, Tennessee. Running back Leonard Fournette showed up for the first OTA but skipped the next nine. Cornerback A.J. Bouye skipped the first three OTAs to work out on his own.

Again, those workouts are voluntary, but Marrone said they are valuable when it comes to building team chemistry. OTAs were one of the things he discussed during his final team meeting this week.

"We know that they are not mandatory, except for the minicamp," Marrone said. "If you want to build a team and you want to be close, and what's a proven fact is that when you're working with teammates and you're competing against them, you'll perform higher than when you're not with them. That's been the case since the beginning. We talked about 100 percent participation of our players when they come back for Phase 1, Phase 2 and the OTAs and minicamp that is mandatory."

Best of NFL Nation • No tailgating allowed! Lambeau on hold

• Broncos' Jeudy on how 'failure is growth'

• Can Giants' Slayton produce like a No. 1?

• Rams' Donald a 'monster' task for Eagles

• Ranking NFL stadiums 1-28

Everyone showed up for the start of training camp except for Ramsey, who missed the first week after the birth of his daughter. That caused some grumbling among a few players, but Marrone excused the absence. Things got worse after that.

Defensive ends Dante Fowler Jr. and Yannick Ngakoue got into a post-practice altercation in full view of the media, and Ramsey went on a profanity-laced tirade at reporters filming the incident. He then threatened a reporter who posted video of the altercation on social media and was subsequently suspended -- along with Fowler -- for a week.

GQ Magazine chose that moment to publish a story on Ramsey in which he ripped numerous NFL quarterbacks, most notably calling Buffalo Bills rookie Josh Allen "trash."

None of those things seemed to matter after the Jaguars got off to a 3-1 start that included a victory against New England in Week 2. But a five-turnover game by quarterback Blake Bortles in Kansas City and an embarrassing rout in Dallas started a seven-game losing streak. A loss to Philadelphia in London was included in that streak. Two days before the game, safeties Barry Church, Ronnie Harrison and Jarrod Wilson and cornerback D.J. Hayden were arrested at a nightclub for failing to pay their tab.

The loss to Philadelphia was one of six games Fournette missed because of a right hamstring injury. There was frustration inside the organization about how much time he missed, with some questioning his level of commitment to returning as quickly as possible.

Things weren't much better in terms of accountability on the field. The Jaguars committed the third-most penalties in the league (121) and had the most unsportsmanlike conduct/unnecessary roughness penalties (36). Twenty-one of those penalties came on defense, and among those was a taunting penalty on linebacker Telvin Smith as he returned an interception for a touchdown.

Smith said after the game he wasn't sorry and likely would do it again: "Don't think you're going to chase me down and tackle me when I got the rock. I'm going to point at you and get you right."

The NFL suspended Fournette for a game without pay after he left the bench, ran across the field and punched Buffalo defensive end Shaq Lawson during a Nov. 25 game. In his first game back after the suspension, Fournette was caught on video yelling at a fan in the Nissan Stadium stands that he would "beat your ass." Fournette said the fan used a racial slur.

It was a frustrating season for Jaguars running back Leonard Fournette, who struggled to stay on the field because of injuries and a suspension. Photo by Zach Bolinger/Icon Sportswire

Fournette was involved in another incident that drew the team's ire. He and running back T.J. Yeldon sat on the bench and acted disinterested in the game throughout the season finale. Fournette was inactive because of a foot injury (his seventh game missed because of injury) but Yeldon was active, and Coughlin lit into both in a postgame statement that called the two "disrespectful" and "selfish." The statement also said "their behavior was unbecoming that of a professional football player."

Other examples of a culture problem:

Defensive end Calais Campbell was spotted restraining Ngakoue from going after a teammate in the locker room just before the media was allowed to enter after the team's loss to Houston on Oct. 21.

Marrone said an unnamed player refused to go into a game.

Marrone admitted he might have given the players the benefit of the doubt and too much leeway in 2018 after their success in 2017, and that resulted in the players either ignoring or not responding to his approach. That's not going to be the case in 2019, Marrone said.

That hints at a more rigid daily structure, more significant penalties for misbehavior (though there are maximum fines teams can impose), zero tolerance for being late to or missing meetings or rehab sessions, and a message that anything but a complete and total buy-in is unacceptable. Think Coughlin, circa 1995.

That might mean having to make personnel changes -- Fournette could be at the top of the list -- but the players need something to focus their attention. Marrone said he's not going to go into specifics, but he has ideas he will present to Coughlin and general manager Dave Caldwell before the players return. Marrone said what happened in 2018 will not be tolerated.

"Obviously, I didn't do a good enough job, so that's something I'm going to have to look at and see where I'm at with that, because you're not getting the results that you want," Marrone said. "You have to look at how you handle things. It's tough when you look at what I did differently this year to last year.

"I will be very, very critical of myself, but I can promise you I will not make that damn mistake again."