When whispers began circulating at the end of the summer that a number of high-profile United States women's national team players would be making their way to England, there was curiosity on both sides of the Atlantic as to what this might mean for the global game.

Several players had done stints in Europe before, of course, but the arrival of five of the 2019 World Cup winners' top stars -- Alex Morgan, Tobin Heath, Rose Lavelle, Christen Press, and Sam Mewis -- to England was a marked difference to previous moves that had drawn criticism and even seen national team careers threatened.

Jump to: A few minutes with Matthew Hoppe | Stock watch | Scouting report: Chris Richards

In 2018, Portland Thorns and USWNT star Crystal Dunn cut her time at Chelsea short over fears her national career would suffer, while Morgan (Lyon) and Carli Lloyd (Manchester City) also previously faced criticism after leaving for opportunities abroad.

Former United States manager Jill Ellis was a strong advocate of players remaining in the USA and the USWNT's existing pay structure makes playing outside of the U.S. quite complicated for players, especially if they don't have the support of U.S. Soccer. The federation pays the players' international salaries and game bonuses, as well as the club salaries for USWNT players who play in the National Women's Soccer League (NWSL). While teams own the league, U.S. Soccer are employed through a contract to manage aspects of the league. This includes paying national team salaries for some players as well as salaries for at least 22 other players. In exchange for these salaries, the teams and the league limit the amount of players who can go overseas, though this contract is revisited periodically and the next review is due at the end of 2021. It all means that the USSF has an extra interest in its big stars staying home and playing in the States.

However, these controls have been loosening in the last year due to a number of internal and external factors. The league has been looking to lessen the control U.S. Soccer has on its players while Ellis' successor as USWNT coach, Vlatko Andonovski, has said he sees the benefits of players getting experience abroad.

"Every player that is Europe-based, if they're healthy and performing well, they're going to be in our plans and will be called for upcoming camps," Andonovski said when asked about the Europe-based members of his squad.

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However, one factor undoubtedly pushed the balance for the players this year: the COVID-19 pandemic. Even though the NWSL was the first professional sports league to return to play in the United States after the initial pandemic-enforced shutdown, uncertainty led to Press and Heath opting out of the league's Challenge Cup, while Morgan's club side, the Orlando Pride, were forced to withdraw from the tournament entirely due to a spate of COVID-19 tests.

"It was a really impossible situation," Heath told ESPN. "I haven't played a real game of football since March, and it was a long time to press pause on my career. It was a very tough decision because I have given so much of my career and my heart there.

"The NWSL is a great league. It's so competitive from every single team and every single game. They have the right people and they are invested in it. It's unfortunate that the outcome right now isn't players staying."

Man City's Mewis (North Carolina Courage) and Lavelle (OL Reign) did compete in the tournament, but the chance for regular football ahead of an Olympic year was a massive draw.

"I think the NWSL did such a good job with the Challenge Cup," Mewis told ESPN. "I think it is such an individual decision to switch teams or change leagues, and the opportunity is so great that I personally was like this is a chance for me to add some depth to my game and continue to evolve as a player."

Not only was the certainty of England's FA Women's Super League (WSL) season a draw for the players, but their coaches also backed them for pursuing regular game time and continuing their development. "Most important for Sam right now are competitive games, especially leading into an Olympic year, and she will be able to play 20 games over the next six to seven months, which is hugely valuable," North Carolina Courage coach Paul Riley said when her transfer was announced.

While the winds may be slightly changing for the USWNT, it is unlikely -- especially with the return of the NWSL and several new expansion teams coming soon, like Racing Louisville FC and Angel City FC in Los Angeles -- that these moves will herald a mass exodus to Europe. The role of COVID-19 and subsequently a lack of domestic options for players also cannot be understated, with Morgan announcing on Monday she will be leaving Spurs to return to Orlando in January.

However, as women's football becomes a more global game and the ties between U.S. Soccer and the league continue to loosen, it wouldn't be surprising to see more of the USWNT' stars make the move across the pond in the future. -- Kathleen McNamee

A few minutes with ... Matthew Hoppe

Schalke 04's Matthew Hoppe is the latest young American to break through in the German Bundesliga, the 19-year-old having recently made his Bundesliga debut against Borussia Monchengladbach.

The Californian, who has made three appearances to date for Schalke, is hoping to make his USMNT debut soon and sat down with ESPN's Sebastian Salazar to discuss the future of the USMNT, his unlikely rise at Schalke and which strikers he models his game after.

Stock watch: Assessing the ups and downs of Americans abroad

Tobin Heath, Manchester United -- On the rise : Coach Casey Stoney's work to secure the signatures of USWNT stars Tobin Heath and Christen Press at Manchester United was one of the biggest coups of the summer transfer window. Heath in particular has made her presence felt since her arrival at the club, with her distinctive and confident play helping United head into the Christmas break top of the WSL table. With United still a relatively young side, Heath's four goals have been impressive, but her leadership and experience have undoubtedly been just as important to the Red Devils' success so far this season.

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Tim Weah, Lille -- On the rise : After a lost 2019-20 season due to multiple hamstring injuries, Weah is finally starting to make his mark in France. The American attacker has made the most of his appearances of late, scoring goals against Celtic and Dijon and adding an assist against Slavia Prague in the month of December. Weah has yet to start a game in Ligue 1, but it seems as if that is only a matter of time now.

"He has improved massively. He is getting better and better. We forget sometimes that he is only 20 and that he had a very serious injury last year. He is working really hard, and we have great hopes for him for this season," a Lille source tells ESPN's Julien Laurens. Healthy and confident again, Weah looks as if he is getting back to his best, which is great to see after an injury-marred 2020 for the ex-PSG man.

Tyler Adams, RB Leipzig -- Trending down: Adams remains a contributor for RB Leipzig, but some around the team worry about his form and his competition for the starting defensive midfield role. After scoring the goal that sent RB Leipzig into the Champions League semifinals in August, the 21-year-old has endured a mixed start to the season, marked by inconsistent playing time and a minor knee injury.

The American has started seven of Leipzig's 13 games in the Bundesliga, six of those as a defensive midfielder, but faces competition from both Marcel Sabitzer and Kevin Kampl in the heart of the pitch. Ulli Kroemer of NTV rates him behind Sabitzer and Kampl in terms of ball control and adds that at the moment, Adams lacks the class and experience that the other two possess. Maybe more troubling is that Kroemer also says that Adams has struggled to win back balls of late, which is one of the attributes the former New York Red Bulls product typically hangs his hat on. Adams will need to turn it around soon or he could be the odd man out in Julian Nagelsmann's constantly changing midfield.

Rose Lavelle, Manchester City -- Trending down: Picked to the NWSL Challenge Cup's Best XI, Lavelle's arrival at Manchester City was met with real excitement. However, it feels like we've yet to see the best of the midfielder across the Atlantic. Manager Gareth Taylor has said that she arrived to the WSL with a different level of fitness to teammate Sam Mewis, which is why her game minutes have been somewhat limited. A goal against the Netherlands for the USWNT in November was a timely reminder of what she is capable of, however an injury soon after set her back again. Many will be hoping 2021 is the year she banishes any fitness doubts and establishes herself as a key cog in the Man City machine.

Scouting report: Chris Richards

The young American defender has enjoyed a fairytale 2020-21 season so far. In the space of a few eventful months, the Alabama-born center-back has gone from a talent to a proper pro, starting for Bayern in the Bundesliga and the Champions League and making his debut for the USMNT against Panama. The 20-year-old's journey to the German champions hasn't been the easiest -- he had to undergo a trial and a loan move before his permanent €1.1 million move from FC Dallas -- but he's passed every exam along the way with flying colours.

Fielded mainly as a centre-back for Bayern's second team in the third tier of German league football, Richards has alternated between his preferred position in the middle and as a right-back for the senior side. Despite being mobile, he doesn't have the extreme pace of his teammate Alphonso Davies and at centre-back, but his obvious qualities -- aerial power (he's got a great leap), composure on the ball, and one-on-one defending -- come to the fore much more readily.

While not quite yet ready to permanently replace Jerome Boateng or David Alaba (whose contracts expire at the end of the season) in the first team, the accumulated playing time and faith he's been shown by Bayern head coach Hansi Flick will work wonders for his further development. With work on his positional and game-reading skills, he'll have every right to envisage a future as a regular starter for the reigning Champions League holders. - Tor-Kristian Karlsen