BUFFALO, N.Y. - During his trip to Western New York on Monday, Roger Goodell said -- again -- that the Buffalo Bills will need to explore building a new stadium at some point in the not-so-distant future.

The NFL commissioner's comments were not surprising, and they were not new. Other team owners, namely Jerry Jones, have also made similar statements over the past few years.

Their incentive for a new facility in Western New York isn't hard to grasp. The league and other owners would make millions and millions of dollars in additional revenue if the Bills were to build a fancy stadium, because every home game the Bills play makes money for the other 31 franchises. The Bills themselves could obviously grow their profits, too, but Terry and Kim Pegula have only hinted vague interest in a new stadium. They have not committed to anything specifically, and now that they own the team with no plans to relocate, they said the decision is not especially urgent.

But that pressure from Goodell and other owners may only intensify over the next few years, with the end of the Bills' lease approaching in 2022. The Ralph underwent $130 million of renovations just two years ago, but it's still one of the league's oldest facilities.

There are many more questions than answers about this hypothetical new stadium: nobody has decided where it would be built, how it would be built and who would pay for it. Erie County Executive Mark Poloncarz has, in no uncertain terms, railed against the NFL for suggesting a new stadium is necessary. He's asked the league for proof that the Bills can't stay viable in the Ralph.

But if a stadium project were to ever move forward in Western New York, public subsidies would almost certainly be involved.

Andrew Zimbalist, an economics professor at Smith College and one of the country's top sports economists, said the public financing for NFL stadiums varies from city to city. Levi's Stadium in the Bay Area, for example, isn't financed as heavily by the public, because the region is wealthier and local governments have more leverage.

"They're on the lower end, 15 to 20 percent for public financing for the stadium," Zimbalist said. "But smaller cities are up at 80, 90 and 100 percent of funding for the stadiums."

Raymond James Stadium, the home of the Tampa Bay Buccaneers, is indeed financed 100 percent by the public in Tampa. More recently, taxpayers chipped in about a half-billion dollars for the new home of the Minnesota Vikings. In 2008, taxpayers footed more than $600 million for Lucas Oil Stadium. In St. Louis, a proposal to build a new stadium for the Rams with public subsidies wasn't even enough to convince the owner to keep them in town.

On Monday, Goodell didn't go as far as saying he believed the Bills needed a new stadium to stay in Western New York long-term, but he was making a strong suggestion the franchise can only stay viable by adding a better facility.

"I don't think you'd see Roger Goodell making that threat to the New York Jets or the New York Giants. Or for that matter the team that's now going to become the Los Angeles Rams," Zimbalist said. "Buffalo doesn't have bargaining power here."

Nellie Drew, a adjunct professor of sports law at SUNY Buffalo School of Law, said she believes the Pegulas were ultimately make their own decision, instead of caving to NFL pressure.

"I think that conversation will be had, not so much in response to NFL pressure, but in response to what the Pegulas perception is of the business reality of the situation," Drew said. "I think that's a very good position for the people of Buffalo to be in. We know the Pegulas are excellent business people, and very invested in the community."

Goodell did say on Monday that these decisions are, in the end, left to the local governments and the team. They must choose what's right for the community, Goodell said.

As a whole, research has consistently shown that the stadiums themselves do not have a substantial economic impact on a region as a whole. Zimbalist has written entire books about these subjects.

But he did say that a full mixed-use development, in combination with a new facility, could lead to a modest impact under the right circumstances.

"Depending on if you have a larger mixed-use development project with retail, with commercial, with themed activities, with residential, depending on what the project is," Zimbalist said. "Depending on what the city's needs are, depending on how it's financed, depending on public subsidies... maybe it could work out."