In a signal that their bid to land a big league soccer team is serious, the St. Paul City Council, the city’s Port Authority and the Metropolitan Council each will vote Wednesday on an agreement formalizing talks aimed at leasing a vacant site in the Midway for a soccer stadium.

Although the Port Authority and the Met Council have been conducting such talks for several weeks, the joint powers agreement expected to be approved next week will provide “a framework” for ongoing communication and negotiations among the parties, officials said Friday.

The Star Tribune reported last month that St. Paul is the choice of Minnesota United FC owners as the new home for a stadium. Since then, MLS Commissioner Don Garber has toured the site and said he was “impressed” with its central location, proximity to transit and development potential.

Eric Durkee, spokesman for Minnesota United FC, said Friday that team officials were “pleased to see a further demonstration of St. Paul’s commitment in helping to ensure that Major League Soccer comes to Minnesota.”

“We want them to know, and the league to know, that we’re serious about this,” Port Authority spokesman Tom Collins said.

The Port Authority, an independent agency that often works with the city on development projects, is negotiating with the Met Council on the city’s behalf because of its experience with leases.

The agreement itself provides only a few details on what negotiators are considering for the vacant 10-acre site, a former bus storage area at Snelling Avenue and Interstate 94.

It indicates that the city would lease the site from the Met Council, which would continue to own the land. The team, owned by Bill McGuire and a group of investors, would deed the stadium to the city once it finished building it.

The agreement doesn’t say which party would cover the stadium’s operating and maintenance costs. Nor does it indicate the dollar amount of the lease or what period of time it would run beyond “long term.” Those details have yet to be finalized, Collins said.

Both sides will exchange information on the property, including appraisals that would be used to determine a price on which lease payments would be based.

Ultimately, the team would reimburse the city for lease payments or take over the lease, Collins said. The Met Council would use lease payments to cover transit-oriented improvements around the stadium, such as information kiosks, plazas and walkways.

McGuire has pledged to build the $120 million facility with private funding, but city ownership would help ensure the property is tax exempt — a key condition for the investors, who include members of the Pohlad family and Star Tribune owner Glen Taylor.

The City Council and the Met Council have the agreement on their Wednesday agendas, and the Port Authority has called a special board meeting for that day to vote on it.

But the deal is far from done. Although city officials support the tax breaks the owners want, McGuire and his investors still need the Legislature to approve them. The deal also requires a green light from the Federal Transit Administration, which helped finance the purchase of the property.

The final decision on a stadium site will be made by the league, perhaps not for several months.

The agreement also notes an ongoing lawsuit against the Met Council by adjacent property owner RK Midway, which is seeking compensation for alleged damage done to its property during construction of the light-rail Green Line.

St. Paul’s bid for the project began in earnest last summer, after Minneapolis officials failed to put forth a stadium proposal for a site in the North Loop that the team had favored. Minneapolis and Hennepin County officials say they continue to be interested in working with team owners on a stadium plan.