MLS commissioner Don Garber was on his way to St. Paul, Minnesota, on Monday morning as an expansion timeline slowly comes into focus and the league’s board of governors eyes what could be a critical December meeting.

We still know only one thing for certain: Atlanta United will enter MLS in 2017 and play at the stadium under construction adjacent to the Georgia Dome. Ideally, MLS would like to add two expansion teams at a time, as it did this year with New York City FC and Orlando City. The league prefers to avoid the scheduling issues that result from fielding an odd number of clubs. Atlanta will boost the rolls to 21.

Now that Los Angeles FC has confirmed it won’t be ready until 2018 (at the earliest—a push back to 2019 is possible), one of two teams conceivably could come in with Atlanta. Both would need temporary stadiums, and one would require a significant and surprising decision by the MLS owners.

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Minnesota United is one of those hopefuls. Its place in MLS is secure, but when and where it will start are issues. The NASL club plays at the National Sports Center in Blaine, Minnesota. The bare-bones stadium seats just under 10,000 people and is located about a half-hour north of the Twin Cities. It’s unlikely ever to be a suitable MLS venue, even for a single season. But United would prefer to enter the league in 2017 if possible, rather than wait until a new facility is ready.

That leaves the University of Minnesota’s TCF Bank Stadium and the Minnesota Twins’ Target Field among the potential temporary homes. Twins owner Jim Pohlad is a United investor.

Meanwhile, United is nearing the finish line in its pursuit of a permanent, soccer-specific stadium. The Minnesota state legislature’s failure to address a request for tax relief before adjourning in May slowed the club’s progress. United held an option to purchase a piece of Minneapolis property close to Target Field and the city’s farmers market and pledged to finance construction, but the team was unable to pull the trigger absent the customary tax relief on land and construction materials.

Enter St. Paul and a 10-acre site in Midway, an appropriately-named neighborhood about halfway between the Twin Cities’ downtowns. A former bus depot, the property is adjacent the interstate and two blocks from a light rail stop. Just as crucially, it’s already off the tax rolls. St. Paul, already home to the NHL’s Minnesota Wild, wants United. The city council offered its unanimous support for a stadium in an August resolution, and now it doesn’t have to worry about being used as leverage. United’s option on the Minneapolis land has expired.

Regarding legislation required for a tax break on construction materials and other bureaucratic considerations (St. Paul must be granted the authority to own the stadium, for example), state senate majority leader Tom Bakk said recently, “I don’t think that’s a really heavy lift.” (See this comprehensive breakdown by Minnesota soccer site Northern Pitch for additional details.)

Assuming Garber gives St. Paul the thumbs-up this week, United should be on its way. Site preparation would start shortly and the state legislature reconvenes in March, when the club should receive final approval. That will leave time to finish construction by early 2018. Whether that year is Minnesota’s first or second in MLS remains to be seen.

An answer could come this winter, when MLS is expected to reach a decision regarding a framework and/or timeline for the next round of expansion. The board of governors will meet in December at the site of the MLS Cup final and an announcement could come at that time or shortly thereafter, according to sources.

In 2013, the league committed to fielding 24 teams by 2020. LA and the Uniteds make 23 and David Beckham’s Miami outfit was expected be No. 24. Beckham, Marcelo Claure and their colleagues continue to focus on a site adjacent to Marlins Park, just west of downtown.

“There has been a lot more progress [in Miami] lately than in the last 12 to 15 months," Garber told reporters in England this month. "We have to finalize a whole bunch of deals with the city and the landowners but the site has been selected."

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A Miami stadium timeline is unknown, however, and easily could drag into 2019 or beyond. If MLS wants to hit the 24-team threshold earlier or intends to avoid adding only one new team in a given year, then it may have to look toward Sacramento. There, the USL’s Republic has suffered no sophomore slump. The club continues to sell out Bonney Field (capacity 11,442) and it is in position to expand it by some 3,000 seats if necessary. MLS could play games there while a new stadium is constructed. The hold-up: Sacramento’s expansion application remains unapproved.

Republic, whose investor group includes owners of the Sacramento Kings and San Francisco 49ers, continues to press ahead on its proposed stadium at the Sacramento Railyards. It has hired an architect, HNTB, and expects to conclude design development in November. Construction could begin as early as March. Republic’s mission not only is to make it impossible for MLS to say no but also to be so far along that the league considers admitting Sacramento early. One source said MLS may prefer Sacramento to enter in 2019 (in the new stadium), but the board of governors still may consider Republic’s pitch in December. It’s conceivable that Sacramento is the most MLS-ready partner for Atlanta in 2017.

Beyond Sacramento, there are no clear-cut candidates for clubs after 2020. The existing team most frequently mentioned, the NASL’s San Antonio Scorpions, lacks an owner able to finance an expansion bid. In the spring, Scorpions founder Gordon Hartman hired Citigroup to arrange the sale of the team and Toyota Field, which would require significant upgrades to be MLS ready. No buyer has emerged. San Antonio is the country’s 25th-most populous metropolitan area and 33rd-largest media market (TV households).

MLS is interested in St. Louis, home to first-year USL team St. Louis FC, thanks in part to the city’s commitment to support the construction (with public money) of a riverfront stadium for the Rams, who are weighing a return to Los Angeles next year. Garber visited St. Louis in May and met with Missouri governor Jay Nixon, mayor Francis Slay and members of the task force that’s driving the stadium effort. St. Louis boasts a storied soccer tradition and a metro-area population of some 2.8 million. St. Louis FC is drawing nearly 5,000 fans per game in suburban Fenton, Missouri.

“The optimum environment for us is to play in a soccer-specific stadium,” Garber told the St. Louis Post-Dispatch. “That will always be our goal, but it’s not always achievable in every market. It’s certainly much more attractive when a football stadium is built with MLS in mind, and that’s the plan that these folks have done.”

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Without an ownership group, however, St. Louis is a non-starter. With expansion fees during the current round topping $100 million, buying in for 2020 and beyond will require some well-heeled investors to step forward. “I think there will be no shortage of people who will be interested in owning a team,” Garber said.

No other cities have separated from the competition.

MLS believes a December or January announcement regarding a potential framework for the next round of expansion could generate some movement, according to sources. Groups in Austin, Charlotte, Detroit, Indianapolis, Phoenix and San Diego are among those that have expressed some level of interest.

There’s activity below MLS as well, as the NASL and USL jostle for position. With 11 teams, the second-tier NASL is at a crossroads. It’s unhappy with the U.S. Soccer Federation’s proposal to revise standards for first division leagues, which would necessitate significant—and perhaps prohibitive—expansion and stadium construction if the NASL intends to meet them. The NASL believes second division status mitigates investment, but it must find new owners to cement its long-term viability. It already has Miami FC and Puerto Rico FC scheduled to start in 2016. But Minnesota is on its way to MLS. The Atlanta Silverbacks are league-owned and face the 2017 arrival of Atlanta United, while the Carolina Railhawks are looking for new owners because of the legal troubles facing Traffic Sports USA. FC Edmonton remains isolated and is drawing fewer than 2,800 fans per game.

The NASL is meeting with potential ownership groups in San Francisco, Los Angeles and/or Orange County, California, and Chicago. Nashville, Las Vegas and Birmingham, Alabama, also are on the radar, while discussions in Hartford, Connecticut, have ended for now. Prospects in Oklahoma City and Northern Virginia previously fell through.

The third-tier USL, which intends to pursue second-division sanctioning, is fielding 24 teams this year and plans to add FC Cincinnati, Rio Grande Valley FC, and an unnamed club in Lehigh Valley, Pennsylvania, next year. Sporting Kansas City and Orlando City also will launch their USL teams. SKC’s will play at Swope Soccer Village in Kansas City, Missouri’s Swope Park, while Orlando currently is considering a couple of locations for its team. Reno, Nevada, already is on board for 2017.