CHARLOTTE, N.C. — Sports marketer Max Muhleman, who was credited with the concept of developing the permanent seat license in professional sports and helping the Carolina Panthers and Charlotte Hornets land expansion teams, has died at 88.

Muhleman died on Saturday in Charlotte peacefully after battling some heart-related issues, his son Lee Muhleman told The Associated Press.

Muhleman worked closely with Panthers founder Jerry Richardson in his quest to bring an NFL franchise to the Carolinas in the early 1990s. Muhleman delivered the closing marketing pitch at the October 1993 owners’ meetings for Richardson, who would ultimately be unanimously awarded the league’s 29th franchise.

The Panthers began playing in 1995.

“I don’t think a lot of people realize what a big role Max played in getting the expansion team," said former Panthers director of communications Charlie Dayton. “He wasn’t out front, he preferred to be in the background. That was him. But he was as valuable as anybody in the process of getting a team. He was there every step of the way.”

Muhleman's marketing plan for the Panthers included landing three NFL preseason games in Raleigh and Chapel Hill, North Carolina, and another in Columbia, South Carolina.

All three games sold out, helping prove to league owners that the Carolinas were a viable market.

Still, there was the matter of funding the expansion team.

Richardson didn't want to use taxpayer money and the league was worried at the time about him taking on any additional debt.

That is when Muhleman invented the concept of the PSL, where fans could pay a one-time fee for the annual right to buy season tickets. The Panthers sold more than 55,000 PSLs and the millions raised from that venture were used to build the 72,000-seat Bank of America Stadium in downtown Charlotte.

The stadium continues to serve as home of the Panthers and the Charlotte FC Major League Soccer team.

Tamera Green, who worked with Muhleman for more than a decade and now serves as the senior vice president and communications officer with the Panthers, said Muhleman was an incredibly talented and creative man.

“He had some really cool ‘firsts’ in sports,” Green said. “The idea of the PSL almost came out of desperation at the time. It was like a Hail Mary. And it worked."

Several other professional sports franchises have since adopted the idea of PSLs as a means of funding private stadiums and arenas.

The Panthers still use PSLs.

Earlier in his career, Muhleman worked alongside then-Hornets owner George Shinn to develop the strategy and pitch that would help Charlotte land an NBA expansion team in 1988.

“Max was instrumental in leading the NBA's expansion efforts to Charlotte and establishing the Hornets franchise,” the team post on social media Thursday, calling him a “renowned sports marketing legend.”

He also advised Rick Hendrick when he was looking into becoming a NASCAR team owner.

“Rick has always said Hendrick Motorsports would not have happened without Max Muhleman, who approached him about starting a NASCAR team more than 40 years ago,” wrote former NASCAR driver Jeff Gordon, who now serves as vice chairman of Hendrick Motorsports.

Lee Muhleman said his father's greatest quality might have been his ability to develop and maintain personal relationships.

“He loved sports," he said. “What he was able to do, because of his background as a top-notch sports journalist, was make people he spoke to feel important and liked. He made them feel that they wanted to do business with him. It was the cultivation of not just clients, but friends. And he went on to sustain relationships with all of his clients.”