Owners of the National Football League's Minnesota Vikings are joining the Nashville ownership group trying to bring a Major League Soccer expansion franchise to Music City.

Mark Wilf, his brother Zygi, and cousin Leonard, in their 13th season as majority owners and of the Minnesota Vikings, have signed on as a minority owner of Nashville Soccer Holdings, the business enterprise led by billionaire Nashville businessman John Ingram.

Though terms of the arrangement, including financial details, are not being disclosed, Ingram will remain the lead owner of Nashville's MLS expansion team. Ingram's holdings company recently bought the rights of Nashville SC, a United Soccer League franchise vying for an MLS expansion franchise.

The addition of the Wilfs, who each reside in the New York/New Jersey area, brings the first out-of-state ownership stake to the local effort, while also adding cachet and professional sports expertise to Nashville's MLS pursuit.

Ingram said the Wilfs' involvement demonstrates growing momentum for Nashville's MLS push as 12 cities vie for four spots that the league wants to fill.

He noted how the Wilf family has experience running a sports franchise — including overseeing fan experience, marketing, communications and ticket sales — and leading the development and construction of a new professional sports stadium.

"Those are both areas that will be very helpful to us, and we're really thrilled to have them as part of our efforts," Ingram said.

"This is a sophisticated family that could invest its money in a lot of places," Ingram said. "It's an endorsement for both soccer in the country and Nashville as a market that has a bright future with this sport."

Wilfs attracted to Nashville's 'vibrant, growing market'

The Wilfs, the sons of Holocasust survivors who immigrated to the United States, made their fortunes primarily in real estate development. The Wilf family, whose net worth is billions, purchased the Vikings in 2005 for a reported $600 million. Today, the team is worth an estimated $1.6 billion.

In 2015, the Wilfs had applied to be the majority owners of a new MLS expansion team in the Twin Cities, Minnesota United FC, which began play this year. But their bid lost out when the league instead awarded the franchise to Bill McGuire. MLS, which preferred an outdoor stadium, didn't support the Wilfs' vision for MLS soccer being played in a fixed-roof stadium.

"We appreciate John Ingram and the Nashville passion for soccer, and we believe in how they're approaching it," Mark Wilf said in a phone interview with The Tennessean. "I've known John for several years and we're excited to be part of their team.

"We've gotten to know how Nashville is a vibrant, growing market, and I think it will be incredible — MLS in Nashville," he said, pointing to large crowds at a pair of high-profile soccer matches this summer in Nashville. "It's an exciting challenge and we think a great opportunity.

"All in all, there were a lot of factors that came together."

Family has connection to Nashville's Ingram

Mark Wilf is president of the Vikings; Zygi Wilf is the team's chairman; and Leonard Wilf is vice chairman. Each is considered a co-owner.

In recent years, the Wilfs led the construction and 2016 opening of the $1.1 billion U.S. Bank Stadium in Minneapolis, home of the Vikings. The new stadium enabled Minnesota to win the bid to play host for the upcoming Super Bowl LII in February 2018 and the 2019 NCAA's Men's Basketball Final Four.

The family's main connection to Nashville is Mark Wilf, whose son attended Vanderbilt University and who serves on Vanderbilt University's Board a Trustees, where Ingram also serves.

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The two started discussing the Wilfs' experience with MLS and operating the Vikings after Ingram emerged as controlling owner of Nashville's MLS ownership group.

"The more we talked, the more we said, 'You know, maybe it makes sense for us to do this together,' Ingram said. "I'm really pleased that if we should be successful in garnering one of these expansion teams, it's going to be really helpful for us to have their knowledge and resources to call upon."

As part of a possible stadium plan for MLS in Nashville, Ingram and Vanderbilt are exploring the idea of a pro soccer stadium that would also be an off-campus home for Vanderbilt football.

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This year, Minnesota United FC, began play as the league's 22nd team. The team is temporarily playing in the Minnesota Golden Gophers' football stadium and plan to move into a newly constructed stadium in 2019.

"We support that group," Mark Wilf said of the MLS club in Minnesota. "But we as a family and a business looked to the Nashville market and MLS, and have a lot of confidence that it will hopefully be awarded a franchise with the ownership group that John has put together and the great package that John has put together."

Ownership group now a 'blend of local and non-local'

MLS plans to announce the first group of two cities chosen for expansion at their board of directors meeting in December.

Ingram rejected any suggestion that the involvement of the Wilf family undercuts the local roots of Nashville's MLS effort. He said the group is "a blend of both local and non-local" that has retained a majority local status.

"I'll be the base of it, if you will, from an ownership perspective," Ingram said, adding that there will be other local minority owners as well.

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MLS commissioner Don Garber, who visited Nashville last month, has glowed about the city's economic growth and said the city has risen "pretty high on the list" of potential expansion contenders.

Last week, during the league's all-start game in Chicago, he singled out Nashville, as well as Sacramento, Cincinnati and Detroit as four cites where energy for pro soccer has been "off the charts."

Nashville's soccer community has impressed in recent weeks with more than 100,000 people collectively attending a recent CONCACAF U.S. Gold Cup match and English Premier League match at Nissan Stadium.

Meeting on stadium vision set for next week

Mark Wilf cited those strong turnouts as well as the city's enthusiasm during the Nashville Predators' NHL Stanley Cup Final run as major appeals for his family.

"We know about the (Tennessee) Titans, and we know about the Predators, and I think Nashville — a successful, thriving community — can support MLS soccer," he said.

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The Ingram-led ownership group has been in talks with Nashville Mayor Megan Barry's administration about a public-private deal for a new soccer stadium at the Metro-owned Fairgrounds Nashville.

The Nashville MLS Steering Committee had been scheduled last Monday to unveil their stadium vision for the fairgrounds at a Metro Council committee meeting. That meeting was postponed to accommodate a visitation following the death last week of Barry's son. It has been tentatively rescheduled to Aug. 14.

MLS, which has teams planned for Los Angles and Miami to bring its total number of teams to 24, would increase to 28 teams following the planned wave of four more teams.

Reach Joey Garrison at 615-259-8236, jgarrison@tennessean.com and on Twitter @joeygarrison.