Even though the Vikings have never actually threatened to leave the Twin Cities, the chilling possibility of relocation has long shadowed their campaign for a new stadium.

Owner Zygi Wilf has pledged, practically from the day his family took over the team in 2005, that he wouldn't move the Vikings. That doesn't mean the Wilfs couldn't sell the team to someone who might want to leave for more lucrative stadium digs -- say, in Los Angeles, where two stadium plans are forging ahead.

But moving the Vikings wouldn't be an easy sell, sports business experts say.

The NFL's elaborate relocation process -- splashed over six pages on its media website -- and the league's avowed interest in maintaining geographically diverse teams with proven fan bases weigh against the Vikings moving anywhere in the near future.

NFL officials declined to comment for this story. But in the end, the team's portability rests with the NFL's 32 clubs -- three-fourths of which would have to approve the Vikings' exit from the Twin Cities. Much will depend on what the NFL decides about Los Angeles: whether to put one or two teams there, and how.

"The brand name of a league depends on its longstanding franchises, and certainly the Los Angeles Vikings won't be as attractive in branding as the Minnesota Vikings," said Rod Fort, a sports management professor at the University of Michigan. "There should be Vikings playing in a frosty land. That's the whole idea of it."

The NFL considers local corporate support critical to a team's success, and Minnesota ranks high on that score. Only five of the NFL's 32 markets have more Fortune 500 companies than the Twin Cities.

Minnesota even enjoys a measure of protection in the halls of Congress. With the NFL's lucrative antitrust exemption for broadcasting under constant scrutiny, it's noteworthy that both the state's U.S. senators, Amy Klobuchar and Al Franken, sit on the Senate's Antitrust Subcommittee.

Relocating an NFL team today takes time, said Marc Ganis, president of Chicago-based SportsCorp, a sports business consulting firm.

"It's not one of these things like Bob Irsay" -- who famously moved the Baltimore Colts to Indianapolis in the dead of night in 1984 -- "pulling the moving trucks up to the facility. Those days are behind us."

Pros, cons and money

Both Ganis and Fort warn, however, that the NFL's eagerness to reenter the L.A. market could overcome its reluctance to leave Minnesota -- especially if state policymakers go to war with the Vikings.

"If the political and personal attacks can be avoided and the parties look like they're trying to find a reasonable solution, that makes a very big difference," said Ganis, who helped the Raiders and Rams move in 1995. "But where the political class starts trashing the team owner and the team ... that's when Vikings fans in Minnesota should seriously start getting concerned."

Sports economics makes it likely that the NFL is more interested in expanding into the L.A. market than moving an existing team there, Fort said. One reason is TV, and another is what the league stands to get out of expansion.

The NFL's TV ratings in Los Angeles are among the highest in the country even without a local football team, which Fort said helps explain why the league hasn't been in a hurry to fill the gap left when the Raiders and Rams departed.

Moving the Vikings to Los Angeles would sacrifice Minnesota's strong NFL TV market -- fifth-best among 32 teams last year -- without a big boost in the numbers in L.A.

An even bigger factor could be the difference between a relocation fee, which the NFL can levy against an existing team that moves, and an expansion fee, which a new franchise must pay the league. The money is essentially divvied up among team owners.

Two of the last NFL teams that moved -- the Houston Oilers to Tennessee, and the Los Angeles Rams to St. Louis -- paid relocation fees of $28 million and $29 million, respectively, in the mid-1990s.

The league sets the relocation fee, based on what owners believe they're gaining or losing from a move. Some believe a relocation fee today could range up to $200 million; others think a range of $30 million to $40 million is more likely.

But that pales in comparison to the expansion fee, which could run up to $1 billion. The Houston Texans, the NFL's latest franchise, paid an expansion fee of $700 million in 2002; the new Carolina and Jacksonville teams each paid $140 million in 1995. (The tab for the Vikings in 1961? $1 million.)

The relocation dance

The NFL's relocation policy says no team is entitled to move just because it thinks it might make more money somewhere else.

"Indeed, league traditions disfavor relocations if a club has been well-supported and financially successful and is expected to remain so," the policy states.

On the other hand, if a team has tried but failed to resolve its stadium issues, and doesn't believe there's any hope it can, it might ask the NFL to move.