TUKWILA, Wash. — The Seattle Sounders have all but finalized a new USL Pro franchise to play at their Starfire training base. The organization will delay an official announcement until final paperwork is signed, but the USL affiliate is starting to take shape.

“We’re being pretty methodical,” Andrew Opatkiewicz, who will be the USL team’s general manager, told SI.com at Sounders training on Wednesday. “I don’t personally see any realistic chance we’re not going to do it [at Starfire in 2015].”

Starfire, located 20 minutes south of downtown Seattle, houses the Sounders’ training fields and academy. The facility includes fenced-off grass and artificial turf fields, a private locker room and offices and a 4,000-seat stadium where the first team plays its home games in the U.S. Open Cup.

The possibility still exists, if the Starfire deal falls through at the last minute, that Seattle could align with an existing USL team before trying to launch again in 2016. Opatkiewicz said that although the team has looked at playing outside the Seattle area, staying close to home would make the most sense to allow first-team staff to observe the reserves and move players between teams easily.

“If we can do it here in Seattle … then I hope there’s never a reason to take it away from Seattle, to be honest with you,” he said.

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Seattle would be the latest in a flurry of Major League Soccer franchises to announce new USL Pro teams for the 2015 season. The Montreal Impact announced FC Montréal on Sept. 4. Real Salt Lake owner Dell Loy Hansen said Wednesday that his team has a franchise agreement in place for its USL Pro team, which is to be called Real Monarchs.

The LA Galaxy were the first to start their own USL operation. LA Galaxy II finished in third place during the 2014 inaugural regular season and will host a first-round playoff game on Saturday.

The three Cascadia franchises, Seattle, the Portland Timbers and the Vancouver Whitecaps, all could have agreements in place before the USL Pro deadline of Sept. 15 to allow teams to launch in time for the 2015 season.

Franchises in LA, Seattle, Montreal and Salt Lake, as well as any others whose USL teams eventually play in the same city as the first team, are approaching the model in Spain, Germany and other European nations where reserve teams also play in the professional leagues. (Salt Lake houses its academy just outside Phoenix, so unless it moved, top-to-bottom integration for RSL would be slightly more difficult.)

Opatkiewicz said five academy players would be allowed on the USL teams’ game-day rosters, which follows the same formula as the current MLS Reserve League and wouldn’t interfere with NCAA eligibility. But reserve games are often played on training fields with few spectators, while the USL offers a chance to compete for playoffs and a trophy.

“You can’t learn to be a pro until you play in meaningful competition in front of people,” Opatkiewicz said.

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The USL team would play a major role in Seattle’s youth development system, which currently includes its U.S. Soccer Development Academy teams as well as an amateur Premier Development League summer team for academy alumni and other college players to get further looks with the organization.

The second part of the Sounders’ USL roster would be players moving down from the first team for injury rehabilitation and to find playing time, Opatkiewicz said, and the final 10 to 15 roster spots would be filled with players signed strictly to USL Pro contracts.

Sources close to the academy and its alumni players have told SI.com that midfielder Duncan McCormick and forward Victor Mansaray will sign Homegrown Player contracts to help fill out the Seattle USL team. McCormick canceled his commitment to Wake Forest for the 2014 season, citing “different opportunities.” Mansaray played for the United States Under-18 national team in the recent International Tournament of Václav Ježek, which it won.

Other potential Homegrown signings include: Stanford sophomore forward Jordan Morris, who was called up to the senior national team for the recent friendly against the Czech Republic but did not play; Washington senior forward Darwin Jones, who turned down a similar Homegrown contract before the 2014 MLS season; and Portland freshman goalkeeper Paul Christensen, a former U.S. U-17 international.

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Opatkiewicz said, “We have a good idea” of how the USL team would be comprised, but he had no specific confirmations of any potential signings. The organization is beginning to fill staff positions, including on the technical side, but the main priority remains finalizing where the new team will play in 2015.

Next year will be the third in MLS and USL’s collaboration, which looks set to enter a new era already with both leagues continuing to expand and MLS influence now reaching the franchise-ownership level.