Sports Illustrated's Brian Straus broke the story Wednesday morning that Tulsa, Oklahoma, would join USL-Pro in 2015. Colorado Springs was announced a couple weeks ago as an expansion side for 2015, covered by Burgundy Wave, the same year designated for full integration of the league with the MLS Reserve League.

When the landmark affiliation deal was announced in January of this year, 2015 was set as the target for when each MLS club would either reach an agreement with an existing USL-Pro club or create its own "B team" in that league. This past season the Revs were one of four clubs to establish a USL-Pro affiliate with the sadly under-performing Rochester Rhinos. D.C. United, Philadelphia Union, and MLS cup finalist Sporting KC also held partnerships with Richmond Kickers, Harrisburg City Islanders, and MLS-bound Orlando City.

Chad Hollingsworth of Reckless Challenge wrote in November that L.A. Galaxy and FC Dallas might join USL-Pro for 2014 while VSI Tampa Bay FC Flames and Antigua Barracuda FC were likely to fold. The demise of these two clubs, one an expansion side and one an unfortunate Caribbean experiment, has not yet been confirmed by the league but is widely accepted. Dallas looks to be holding off until 2015 to field a team in USL-Pro (as are Seattle Sounders and NY Red Bulls) but the Galaxy is making waves with its intentions to carry forward in the upcoming season.

On November 26, Houston Dynamo and Pittsburgh Riverhounds announced that the two clubs had reached an affiliation deal, becoming the fifth such arrangement. USL-Pro expansion side Sacramento Republic FC is working to finalize a partnership with the Portland Timbers ahead of the upcoming season. On Wednesday Straus also mentioned the possibility of an affiliation relationship between Columbus Crew and Dayton Dutch Lions that was announced by the teams on Thursday. In similar press releases issued by the Crew and by the Dutch Lions, both teams stressed the beneficial nature of this relationship for player development.

In addition to naming former Sporting KC goalkeeper Jimmy Nielsen as head coach, Oklahoma City Energy FC announced they would be a USL-Pro affiliate of the 2013 MLS Cup Champions. Energy FC will join Orlando City as co-affiliates of Sporting KC and therefore will split the guaranteed 4 loaned players.

The infrastructural support that the MLS deal gave USL-Pro has sparked a surge of interest in the third division league that has otherwise seen 6 teams fold (and one former expansion club on life support) since beginning operations in 2011. USL-Pro will add Sacramento Republic FC, a club led by MLS-great Preki with well over 3,000 season ticket deposits, and Oklahoma City Energy FC for the 2014 season, with Colorado Springs and now Tulsa joining the league for 2015. All four of these expansion sides have home venues in place for use when they start play, which is more than the ill-fated VSI could say at this point last year.

The confidence exhibited by the league to add the Tulsa franchise before Oklahoma City, its natural in-state rival, has played a game or even signed a player is either inspiring or worrisome. While most of the news coming out of USL-Pro recently has been positive, those who have been following lower division soccer since before this year have reason to be skeptical. Perhaps this pairing of Sooner State cities 90 minutes apart can grow into a Cascadia-type rivalry, but first USL-Pro has to show that this rapid expansion is viable and sustainable.

USL-Pro is continuing to benefit from its agreement with MLS, landing two more affiliations in this current off-season. These deals allow USL-Pro teams to land at least 4 players from its MLS partner which offsets player salary costs while providing talent, even if the players don't have a Dom Dwyer impact in the league.

There has been much to get excited about recently with USL-Pro but I will reserve a cautious optimism about the quality of its expansion franchises.