It has arrived. The MLS secondary transfer window, a time that traditionally has seen the most star power enter the league, just opened with a flurry of moves. This year may not be any different as plenty of big names are being linked all over the league. There's also some real interest overseas in the league's talent, especially in the emerging stars. It would continue a trend from the past several years of players using MLS as a stepping stone to one of Europe's big leagues.

We detail some of the most mouth-watering moves that could unfold this summer, in this edition of the MLS and U.S. men's national team Rumor Rater.

Aaron Long to the Premier League: 45 percent

It is no secret that Long has been a massive success story for the New York Red Bulls. A player twice cut by other MLS teams before arriving on trial in New York in 2016, Long has blossomed into a star center-back and a U.S. international. On Sunday, FS1 analyst Brian Dunseth dropped a nugget that a Premier League team is hot on Long's trail.

An unnamed Premier League club has made a pair of bids for New York Red Bulls center-back Aaron Long. Ira L. Black/Corbis via Getty Images

ESPN FC can confirm that Long has an offer from a Premier League side. And not only that, a source said that the same club has made two offers to the Red Bulls for the 26-year-old's services. The reigning Defender of the Year in MLS, Long could well be on his way out from the Red Bulls. This after signing a new contract with the club last offseason.

The Red Bulls make, the world takes.

Paxton Pomykal to Europe: 15 percent (right now)

Make no mistake about it, the 19-year-old FC Dallas midfielder is headed to Europe at some point in his career. And it will be soon, especially based off of his form for his club as well as at the U20 World Cup. But here and now, this transfer window, it appears slim for the homegrown product to move to Europe. Sources tell ESPN FC that AC Milan, along with teams in England and Germany, are showing a high level of interest in the central midfielder. It will be interesting to see this process play out, especially with his continued growth in MLS.

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Cristian Pavon to LA Galaxy: 45 percent

This one remains unchanged from the last edition of the Rumor Rater. The Galaxy are interested in the Boca Juniors forward and the 23-year-old has interest in coming to MLS. This is a fact. Whether it gets done, that's the tricky part. A source told ESPN FC that Pavon remains a Galaxy target as there is "still interest and conversations ongoing." The Argentina international is a promising young player with options. The fact that the Galaxy are one of those options is a sign of not just the league's ambition but growth in recent years.

Jefferson Savarino to Europe: 40 percent

Coming off a two-goal performance against the Philadelphia Union this past weekend, Savarino's stock is rising. Talk of a transfer is legitimate with sources telling ESPN FC that Real Salt Lake is hoping to hold onto the player until the end of the season before allowing him to make a move. One La Liga team is expressing interest, a source said, but there is also legitimate interest from the Premier League. Recently promoted Aston Villa is intrigued by Savarino and could table an offer, a source said. Interestingly enough, the English club is currently in the United States on a preseason tour.

Alex Mendez to a Champions League club: 30 percent

After a standout performance for the United States at the recently concluded U20 World Cup, former LA Galaxy academy product Mendez has seen his stock rise in recent weeks. Currently with Freiburg in Germany's top flight, big clubs are already showing interest in the midfielder, who turns 19 in September.

A source said that Ajax and Real Madrid both scouted Mendez during the World Cup and that the interest from the Dutch giants in particular is legitimate. Mendez could see a run with Freiburg in preseason before potentially going out on loan. A move to Ajax, however, might be too good to pass up. It is still far-fetched and not certain, a source said, but the fact that Ajax seems genuinely interested (and has tabled an offer in the past) makes this one worth watching down the road.

Andres Rios to San Jose Earthquakes: 95 percent

Last time the Rumor Rater appeared, the former Argentina youth international was trending in the right direction with San Jose. Now it appears that things have progressed even further. Rios, who can play up top or out wide, has been with San Jose head coach Matias Almeyda at River Plate. This is a move that makes sense given the relationship between player and coach and San Jose's need for another attacking piece. This move is in a good spot. San Jose gets a player who could benefit from a fresh start under a coach who has gotten the most from him in the past.

Joao Plata to Tigres: 10 percent

The out-of-favor Ecuador international has fallen on hard times at Real Salt Lake, with eight appearances this year and just five minutes played since June. Rumors of a move to Mexico are legitimate, with sources telling ESPN FC that there was "strong interest" from Tigres. As of right now, this one doesn't appear likely to materialize as talks have died down.