CHARLOTTE, N.C. -- The Carolina Panthers were the talk of the NFL in 2015, with a league-best 15-1 regular-season record, led by league MVP Cam Newton. Ron Rivera was the coach of the year. General manager Dave Gettleman was considered one of the league's best talent evaluators.

The team had key players such as Newton and middle linebacker Luke Kuechly locked up long term as a foundation for sustained success.

That season, the Panthers made it to Super Bowl 50 but lost 24-10 to the Denver Broncos.

Then, piece by piece -- most recently the early retirement of Kuechly (28) and mutual split with tight end Greg Olsen -- it fell apart to the point they are starting over under new coach Matt Rhule.

“It’s just sad to see how an organization goes from structure and prominence to now what it is today," said Washington Redskins cornerback Josh Norman, a Pro Bowl selection with Carolina in 2015. “There ain’t always rainy days, but geez, you would think somebody would put an umbrella on top of it."

The countless rainy days are why the Panthers are in this position.

“A Super Bowl-caliber team usually stays together and is functional for about six years at best," said six-time NFL executive of the year Bill Polian, who went to three straight Super Bowls with the Buffalo Bills (1990-92) and two with the Indianapolis Colts (2006 and 2009). “The Panthers were almost at the back end of that six-year run during which they went to the Super Bowl."

But what happened to the Panthers wasn’t a gradual decline. They fell off a cliff, with only one winning season in the last four and a 29-35 record since Super Bowl 50.

Before all the change, Norman said he was interested in a return to Carolina if he were released by the Redskins. Now, Norman doesn't see a fast turnaround.

“It sucks, man, to see the old team you had so much success with go through so much turmoil and turnover," said Norman, a fifth-round pick in 2012. “I guess the old Carolina has died."

Here’s a closer look at what happened, and how the Panthers can dig themselves out:

Newton's health

Polian’s Bills went to the Super Bowl a fourth straight year after he was replaced as general manager. His Colts were back in the Super Bowl three seasons after beating Chicago for the 2006 title.

Continuity was key, particularly at quarterback. The Bills had Hall of Famer Jim Kelly. The Colts had future Hall of Famer Peyton Manning.

“Big! Big!" Polian said about the importance of having a healthy franchise quarterback. “No matter what style that quarterback is, he has to be good at what he does, and Cam was [in 2015]. That Super Bowl was probably the apex of his career."

Newton's injuries are part of the reason the Panthers have been different since Super Bowl 50. He has missed 18 games, including the last 14 in 2019.

Former Carolina quarterback Jake Delhomme, who led the Panthers to the Super Bowl in 2003, offered a reminder that Carolina was 6-2 with a healthy Newton in 2018 before the shoulder injury led to a 1-7 finish.

“I mean, let’s fast-forward three years from now and say Patrick Mahomes is healthy for half a season and then the next season plays only two games," Delhomme said of the Chiefs' quarterback. “You’re looking at a different Kansas City team."

Gettleman's regime

Norman didn’t hesitate when asked how the Panthers got where they are.

“Two words," he said. “Dave Gettleman."

Norman has some personal resentment toward Gettleman, now the GM of the New York Giants. He placed the franchise tag on Norman in 2016 and then rescinded it when, in his words, a long-term deal “was not attainable.”

Norman then signed a five-year, $75 million deal with the Redskins.

According to sources, some in the organization didn’t agree with Gettleman's move. When Norman was shutting down opponents’ best defenders in 2015, the Carolina defense thrived. The defense ranked sixth both overall and in points allowed (19.1) in 2015. A year later, they fell to 26th in points allowed (25.1) and 12th overall.

The Panthers were in what Gettleman called “salary-cap hell” -- $16 million over -- when he took over in January 2013. In his first two years, he made unpopular decisions such as cutting all-time leading receiver Steve Smith and all-time leading rusher DeAngelo Williams.

Both had big contracts and were near the end of their careers.

Then word leaked during the 2017 offseason that Gettleman might move on from linebacker Thomas Davis, a player then-owner Jerry Richardson considered the pillar of the franchise.

Gettleman was fired just before 2017 training camp.

Draft mistakes and staff turnover

Many of the key Chiefs and 49ers in this year’s Super Bowl came through the draft, just as the key players did for Carolina in 2015. But draft mistakes have caught up to the Panthers. They used a first-round pick on defensive tackle Star Lotulelei in 2013 and wide receiver Kelvin Benjamin in 2014. Lotulelei moved on in free agency after the 2017 season for financial reasons. Benjamin was traded to Buffalo in 2017 after he failed to meet expectations.

Gettleman also missed on two second-round picks: defensive end Kony Ealy in 2014 and wide receiver Devin Funchess in 2015. That led to using high draft picks the past two seasons to replenish those positions instead of filling other needs.

Only seven of 21 players selected by Gettleman from 2013 to 2016 are on the current roster and five of those players are free agents this offseason. Of the 25 free agents Gettleman signed, none are on the current roster.

Gettleman did make some good choices. Michael Oher, the anchor at left tackle during the Super Bowl year, was one in free agency. Selecting running back Christian McCaffrey with the eighth pick in 2017 was a home run. But overall, the draft and free-agent moves didn’t strengthen the roster enough in the long term.

Then there was the turnover on the coaching staff. The defensive staff lost coordinators in consecutive years with Sean McDermott (Buffalo) and Steve Wilks (Arizona) getting head-coaching jobs.

And continuity was further eroded when Richardson was accused of sexual and racial workplace misconduct and sold the team to David Tepper in 2018.

How they'll try to fix it

Polian had Rhule on his radar while serving on the NFL’s personnel developmental committee. He said there shouldn't be any concern that Rhule has only one year of NFL experience -- in 2012 as an offensive assistant with the Giants -- or that his coordinators also lack NFL experience.

“No one has ever won at Temple, and he did," Polian said of Rhule, who won 10 games with the Owls in both 2015 and 2016. “He’s solid."

Rhule has a "process" that worked as a college head coach, and he'll use that to try to bring the Panthers back to prominence.

“It's about the daily steps,” Rhule said at his introductory news conference. “The daily grind that you have to go through."

Tepper wants to build for the kind of long-term success he witnessed with the Steelers as a kid growing up in Pittsburgh. Much of that will involve rebuilding through the draft.

Most of the team's biggest stars from the 2015 Super Bowl season -- Newton, Kuechly, Davis, Norman, Olsen and center Ryan Kalil – were products of the draft during Panthers general manager Marty Hurney’s first tenure on the staff. Hurney also built the roster that got Carolina to the Super Bowl in 2003.

Tepper is looking to hire an assistant general manager whose strength is on the pro side with the hope of strengthening the free-agent signings needed for success.

But everything begins with the quarterback position, which means getting Newton healthy. Then the organization must decide whether to keep Newton, who has one year left on his contract, in a prove-it year or move on by trading or cutting the first pick of the 2011 draft.

Cutting ties with Newton would be the definitive signal that Carolina is in the middle of a complete rebuild.