The Denver Broncos have as little as two years to determine which of Pat Bowlen’s seven children will step into his shoes — or face having to sell the team.

The NFL has made it clear that it will not allow the process of choosing a successor to go on indefinitely, giving the Pat Bowlen Trust just two years to make “significant progress,” according to people familiar with the situation.

Bowlen hoped to keep the team in his family and a decade ago mapped out a succession plan through the trust, ensuring one of his children would take the lead ownership role.

But he didn’t set a deadline, leaving it to three trustees — including team president and CEO Joe Ellis — to decide which of the children actually has the ability to do the job, The Denver Post has learned.

“It’s incumbent upon us to have made progress toward getting one of the kids in that direction, significant progress, in those two years,” John Bowlen, Pat’s brother, told The Post. John Bowlen is a minority owner of the team.

Although the NFL has not set a precise time limit, John Bowlen said it’s unclear how much longer than two years the league might be willing to wait — if at all.

“Maybe two more, maybe five, maybe none,” John Bowlen said. “We’ll have to see.”

When Pat Bowlen, 70, stepped aside in July as the team’s CEO to deal with the effects of Alzheimer’s disease, team officials made clear his ongoing desire to keep the Broncos in his family.

“I don’t think he anticipated his demise would be as quick as this,” John Bowlen said.

If none of the children can prove to the trustees they have the ability to run the team — and some have shown an interest in trying — then the family must sell, John Bowlen said.

“I think we’ll know in two years who it will be,” he said, “but whether they’re ready to go is another matter.”

John Bowlen said he doubts the NFL would be so harsh as to force a sale if a successor isn’t at least identified within two years.

“I’m not sure (NFL commissioner) Roger (Goodell) would do that to Joe (Ellis) or Pat’s family because they’re that close,” he said.

The NFL did not respond to requests for comment.

History of impatience

But the NFL has a history of impatience when it comes to ownership changes, typically giving no more than two years to hash things out.

The Buffalo Bills sold last week for a reported $1.4 billion, just six months after founder Ralph Wilson’s death. Family members quickly took over teams when other owners died, including the Oakland Raiders, Tampa Bay Buccaneers, Tennessee Titans and Detroit Lions.

And despite the tumultuous sale of some teams — such as the Los Angeles Dodgers and the Los Angeles Clippers — and worries that some new owners might move their franchises, the odds of the Broncos ever leaving Denver appear minuscule.

With its 13-year-old stadium and one of the league’s best fan bases — Nielsen Scarborough recently ranked the Broncos as having the seventh-best market penetration in the NFL and Forbes put Denver with the second-best fan base — the team enjoys unparalleled support.

“I’m sure there are a number of people who would say that if it’s not Pat Bowlen owning the team, it would be better just selling it, but it would not leave Denver,” John Bowlen said.

For now, Pat Bowlen has handed the reins to Ellis, his longtime friend and confidant. And with former quarterback John Elway as general manager and vice president of football operations, the team appears in capable hands.

But that’s temporary.

The future of the Denver Broncos is still very much in flux.

A family operation

From the day the Bowlens purchased the team from Edgar Kaiser in 1984, it was a family operation.

Unable to cover the $78 million purchase on his own, Pat Bowlen turned to his younger brother, John, who was heading the family oil and gas business in Calgary.

The generosity of their wildcat millionaire father, Paul, ensured the Broncos was a family-led legacy.

“Pat wanted to do it on his own, but there was a need to lean into the company for credit, which we did,” said John Bowlen, president and CEO of Regent Resources Ltd. “Dad, on his death bed, said, ‘Don’t feed him to the wolves. Help your brother,’ and we did. It was a family company and so would be the Broncos.”

The Bowlens pretty much shared in the team equally, with Pat having a mild edge in order to satisfy NFL rules that require a majority partner to hold 30 percent.

Brother William Bowlen and sister Mary Elizabeth Jagger sold their interest back to the family in 1996 and 1997.

And when their mother, Arvella Regis Bowlen, died in 2006 at age 90, her interests were divided between Pat and John, making them whole owners of the Broncos, although paperwork shows that the team is held in holding company names.

Little has changed, said John Bowlen, who controlled as much as 49 percent of the Broncos but has been selling interest back to his brother.

At his death, the 40 percent John Bowlen retains today, though inherited by his children, would be sold to Pat’s side of the family, John Bowlen said.

“They’re obligated to take it out of my estate,” he said. “But, ultimately, yes, it all goes back to the family.”

Ellis in the lead chair

Although Ellis sits in the lead chair today, it’s for the taking by one of Pat’s children — who range in age from 16 to 45.

“The desire is for one of Pat’s children to show the ability to step into the role,” John Bowlen said. “The wish is that one of those kids will demonstrate that ability.”

The decision about which child takes over, John Bowlen said, rests with the three trustees: Ellis, 56; Broncos counsel Rich Slivka, 69; and Denver attorney Mary Kelly, 60.

Although John Bowlen remains the Broncos coordinator of corporate sponsorships, he said his work at Regent Resources keeps him too busy to consider trying to take on the team.

“It would take some pondering on my part,” he said, noting the tax implications of such a choice. “It’s not as if I don’t have a say in things now, maybe not day to day, but some.”

None of John Bowlen’s children — four daughters ranging in age from 16 to 41, and a 34-year-old son — are allowed to take on ownership under the trust.

Some of Pat Bowlen’s children already have a foot in the door.

Between Pat Bowlen’s two daughters from his first marriage to Sally Parker, only the youngest, Jane Elizabeth “Beth” Bowlen Wallace, 44, is on board, working as the Broncos’ director of special projects and events.

Her older sister, Amie Bowlen Klemmer, 45, lives in Hawaii.

Three of Pat Bowlen’s children from his 34-year marriage to Annabel Bowlen also work in some capacity with the team or league.

Patrick III, 30, lives in Denver and is the facilities coordinator of the team’s stadium management company.

Twenty-eight-year-old John Jr., named for his uncle, has a master’s degree in business administration, with a concentration in sports and entertainment management, from the University of Colorado at Denver and has held a variety of jobs within the Broncos organization.

Brittany, 24, is a recent graduate of the University of Notre Dame and is a part of the NFL’s junior rotational internship program in New York, which trains participants in the business side of the league.

It’s too early to tell whether Pat Bowlen’s youngest daughters — Annabel, 21, who works in retail, and Christianna, 16, a high school sophomore — will become active with the team and league.

Should the decision to sell be made — by the NFL or the trustees — any ownership change appears likely to include Elway.

“I would think, with all conjecture aside, that he would certainly have the inside track, if he wanted it,” John Bowlen said. “It’s almost a no-brainer.”

And it’s not difficult to see how or why.

“There’s certainly a business precedent for player-led investment groups such as Magic Johnson and Wayne Gretzky,” said Kevin Adler, founder and president of Engage Marketing in Chicago, a sports marketing company. “If Elway were to put the word out to acquire an investment group to get an ownership interest in the Broncos, people would line up.”

The Denver Broncos released a statement early on Sunday morning on behalf of Pat Bowlen and his immediate family:

“Owner Pat Bowlen has indicated a strong desire to keep specifics of his estate planning private, and the Denver Broncos intend to honor his wishes.

“While Mr. Bowlen’s long-term hope is for one of his children to run the team, any speculation on the transition of his ownership to one of them is premature. No timetable has been set for that process by the organization or the National Football League.

“There are no plans for the sale of the Denver Broncos, and the Pat Bowlen Trust will continue to implement the provisions set forth by Mr. Bowlen to keep the team in the Bowlen family.”

Elway, who did not respond to a request for an interview, has privately said he is unwilling to make any speculations.

Begin, end at Elway

While offering the Broncos for sale is likely to draw a number of suitors, insiders say the list would probably begin and end at John Elway.

After all, it almost did before.

In 1998, Elway’s final season as a player, Pat Bowlen offered him a 10 percent stake in the team, according to copies of the agreement filed away in federal and state lawsuits over the deal.

Bowlen had offered Elway even more.

There was a second 10 percent piece of the team, according to the agreement, as well as a job as Bowlen’s special assistant with an intent on eventually naming Elway, a Stanford University graduate, to the post of chief operating officer.

Elway’s ownership deal extended to any NFL team Bowlen might own, according to the agreement. If Bowlen sold the Broncos, Elway would go with him.

With the team still in Denver, Elway would have gotten right of first refusal on any future sale, except for between Bowlen family members.

And if the Hall of Fame quarterback wanted to go it alone, Bowlen agreed to “use his influence to assist Elway in obtaining an NFL franchise if Elway so wishes.”

Although Elway never signed the deal — Ellis was with the Broncos as its executive vice president for business operations and Elway didn’t see much room for himself in the front office — the relationship he had with Bowlen remained sturdy.

Like Bowlen, Elway is one of Denver’s favorite adopted sons, having brought home a pair of Super Bowl victories. He’s a successful businessman with eponymous car dealerships and restaurants.

And Elway and Bowlen — with Stan Kroenke — co-owned the Colorado Crush Arena Football League team, until the league and team folded in 2008.

Elway came back to the Broncos in 2011 as executive vice president of football operations. He soon landed quarterback Peyton Manning and helped the team to its first Super Bowl appearance since 1999, when Elway was named the game’s MVP and lifted the Lombardi Trophy.

Should the Bowlen family have to find a buyer, several NFL watchers say, who better than John Elway.

“Anytime a team has an opportunity to include a well-regarded patriarch of the sport into their ownership — such as the Dodgers and Magic Johnson with the Guggenheim partnership — it’s a desirable thing,” said David Carter, executive director of the Sports Business Institute at the University of Southern California’s Marshall School of Business.

Figurehead athlete-owners are no longer the norm, he said.

“It doesn’t work anymore to bring in an athlete and give him a percentage of the team just to hang in the window,” Carter said. “And at this point in his business career, if Elway pursued an ownership, he might not even need Bowlen, though it would be nice to have that wind in your sails.”

But no matter his past value as a quarterback or current value as a manager and executive — any bid for ownership of the team today will come down to Elway’s partners.

“It seems to me that it would be difficult not to approve of John,” John Bowlen said, “but a mammoth part would be who my partners would approve.

“Ultimately,” he said, “it is about who is with him.”

The NFL today requires a single principal owner to have a 30 percent interest — $420 million if the Broncos’ value is kept conservative, at about $1.45 billion, according to Forbes — and that is likely out of reach for Elway.

“It’s really about whether they are individuals the NFL wants to allow into their treehouse,” Carter said. “Money is critical, but so is knowing the market and having a business plan the league will subscribe to.”

David Migoya: 303-954-1506, dmigoya@denverpost.com or twitter.com/davidmigoya

The Bowlen children

Patrick Dennis Bowlen, right, has seven children, each of whom has the opportunity to become the new principal owner of the Denver Broncos.

Amie Bowlen Klemmer, 45 Mother is Bowlen’s first wife, Sally Parker. Florida International University graduate. Married. Lives in Honolulu with her husband, Dr. Eric “Howie” Klemmer.

Jane Elizabeth “Beth” Bowlen Wallace, 44 Mother is Bowlen’s first wife, Sally Parker. Married. University of Colorado Boulder graduate. Lives in Denver with her husband, John Wallace. Works as Broncos’ director of special projects.

Patrick Dennis Bowlen III, 30 Married. University of Denver graduate. Lives in Denver with his wife, Mary Ellen. Works as Broncos’ stadium facilities coordinator.

John Michael Bowlen Jr., 28 Single. Lives in Denver. University of Denver graduate and received his MBA from the University of Colorado Denver. Works in variety of positions with the Broncos.

Brittany Alexandra Bowlen, 24 Single. University of Notre Dame graduate. Works in NFL’s junior rotational internship program.

Annabel Victoria Bowlen, 21 Single. Lives in Denver. Works in the retail industry.

Christianna Elizabeth Bowlen, 16 Single. Lives in Denver. High school sophomore.

*Editor’s Note: This online archive has been edited to clarify biographical information about John Michael Bowlen Jr. He received his MBA from the University of Colorado Denver.