Most European transfer windows officially open on Thursday, but silly season never stops. You know this. C'mon. It's a 365-day-a-year news cycle.

The date is something of a reminder in the calendar, but just as MLS clubs negotiate and agree to deals in the offseason before the Primary Transfer Window officially opens, European clubs have already tapped their offseason shopping lists. The only difference is now players can be registered to their new squads for competitive matches ahead of the European fixture list kicking off in July with earlier qualifiers for the Champions, Europa and Conference leagues.

MLS players are firmly on the radar of clubs across Europe, an evolution that continues to proliferate and cascade across the continent as barriers are broken at the highest level by Americans, Canadians and MLS exports. All big clubs want to find the next Christian Pulisic, Alphonso Davies or Tyler Adams. The next Miguel Almiron, Reggie Cannon or Chris Richards. We can go down the line for clubs of all sizes.

Though there are a bunch of names below, this isn't meant to be a comprehensive list. That in and of itself is a hugely exciting and encouraging sign.

There are no doubt names we missed, ranging from the fairly obvious to a bit more arcane. Not all transfer news gets reported. Remember how much of a shock it was when Barnsley announced on deadline day last winter they had signed Daryl Dike on loan? Expect more of that this summer, too.

Deal agreed, leaving in the winter

This one is easy! The New York Red Bulls announced Caden Clark's long-rumored move to RB Leipzig will indeed go ahead in the winter, allowing the wunderkind to finish the 2021 MLS season in MLS.

Clark is the latest RBNY favorite to make the jump to Europe within the Red Bull family, following Tyler Adams and Jesse Marsch.

The 18-year-old made his MLS debut last fall and has been among the league's most exciting young talents ever since, with seven goals and two assists across 16 appearances (12 starts) between the regular season and playoffs. He's currently out a few weeks after an appendectomy.

Heavyweight division

In 2020, it was the summer of Brenden Aaronson. This year, all eyes are on Gianluca Busio.

If you are a consumer of this website, or follow even a handful of MLS accounts on Twitter, you'll surely be aware of Busio's situation. A number of European clubs are chasing him. Sporting Kansas City rejected a few bids from Serie A in the winter and have received more this summer. There were reports over the weekend that SKC and Sassuolo had agreed to a $6 million deal for the wunderkind, but sources told MLSsoccer.com that report was premature. Talks remain ongoing with multiple clubs. There was already no need to be hasty, and with Busio now heading to the Concacaf Gold Cup, there's certainly no rush.

Around $6 million, plus incentives and a hefty sell-on clause, may be the ballpark for an eventual Busio deal. Aaronson was sold for $6.5 million upfront, plus incentives to take the fee to $9 million and a sell-on fee.

“I’m not forcing my way out. It’s not like that,” Busio told Sam McDowell of the KC Star a couple of weeks ago. “It’s mutual that we both talked about this from the beginning. This has always been the stepping stone.”

All signs point toward a summer transfer for Busio or, at the very least, an agreed-upon deal for the winter, a la Aaronson last summer or Caden Clark this year.

Busio has started every single game for SKC in 2021 as they remain firmly in the Supporters' Shield chase after a third of their MLS season. His positional versatility is attractive to potential suitors, as he's played as a false No. 9 and in all three midfield roles -- attacking, box-to-box and defensive -- this year alone.

Another player whose situation you'll be familiar with if you find yourself on this website: Daryl Dike has been in the spotlight for the whole of 2021.

Dike's strong form while on loan with Barnsley in England's Championship has seen him linked with seemingly most Premier League teams. He was reported to be the subject of interest from one of England's 'big six' teams in the spring. This summer, the likes of Watford, Everton and others have reportedly chased him.

Orlando have reportedly put a $20 million price tag on the 21-year-old forward. It surely won't be a boring summer.

In the interim, Dike returned to Orlando and has featured in three games. Naturally, he scored two goals. He, like Busio, is headed to the Gold Cup.

Diego Rossi has been a talent to watch since his very first MLS game, scoring LAFC's very first goal in MLS. He has grown from exciting young talent to full-blown MLS star, winning the Golden Boot presented by Audi last year despite missing a number of games while LAFC played far from their best.

The 23-year-old Uruguayan forward is entering the early stages of his prime. How much longer will he be in MLS?

Reading and a few other Championship clubs (ambitiously) reached out to LAFC in the hopes of getting him on loan in the winter, which obviously didn't happen. This summer, The Telegraph reported the likes of Everton and Tottenham are interested, which makes more sense.

His contract expires after 2022. The clock is ticking.

Rumors floating...

Quietly during Atlanta's disappointing 2020 season, George Bello took a big step forward. Long a top prospect, he had firmly broken into Atlanta's first-choice XI. It's been more of the same this year.

Bello, 19, is a regular with the US youth national teams and earned his senior USMNT debut in January. He already has 33 MLS appearances – despite missing all of 2019 with an injury and the 2020 season being shortened to 23 matches due to the COVID-19 pandemic.

The attack-minded left back is reportedly a target for Turkish giants Galatasaray, as well as clubs in England and Belgium, according to Atlanta Journal-Constitution's Doug Roberson. Galatasaray is the home of USMNT right back DeAndre Yedlin.

Bello isn't the only fullback with a Turkish heavyweight interested.

Richie Laryea has been linked with Besiktas after the 26-year-old Canada international grew into a key player for Toronto FC over the last few years, including a career-best 2020 where he had four goals and four assists in 20 appearances (15 starts).

CanMNT legend and Besiktas veteran Atiba Hutchinson confirmed he told his club to sign Laryea.

“Whether it’s Besiktas or another club in Europe, I think he’s definitely got the potential,” Hutchinson said during a beIN SPORTS interview in May. “I really like him as a player. I think he’s good going both ways, very positive and confident in himself, good feet, solid defensively and he’s got what it takes to be a player that can play at a high level in Europe. I had a couple of words with the club, that was my part of advice. He’s somebody that I feel could make a difference. I’ll obviously mention that player to my club or any other club if I feel it's needed. But like I said, I think he’s a good player and he's got a lot of potential."

Brian Rodriguez was on loan in the Spanish second tier with UD Almeria for the first half of 2021, a deal that included a purchase clause that would have been automatically triggered had they gained promotion. They stumbled in the promotion playoffs and Rodriguez was set to return to LAFC.

He hasn't yet returned all the way to LAFC, as he's representing Uruguay at the Copa America. Some cryptic quotes have cycled out from Rodriguez's camp that express frustration, but nothing definitive yet.

Head coach Bob Bradley said they're excited to get him back after the Copa America if a suitable opportunity, both for the player and the club, doesn't materialize in Europe.

“From the beginning, we’ve spoke of his talent and we believe that there’s a lot more there for him to do here,” Bradley said a few weeks ago. “So, no big update other than we’ll wait and see how things play out for the rest of Copa America and then a little bit into the transfer window.”

Like a few others on this list, both Williamson (Ferencvaros TC) and Ebobisse (Anderlecht, Dusseldorf, Zulte Waregem) had overtures rejected last winter. They're of a similar age and profile, plus they're club teammates and good friends, so let's be lazy and group them together.

The Portland Timbers duo is key for Gio Savarese's side – the Western Conference side is getting closer to full strength this summer – though Williamson will be away at the Gold Cup.

Ebobisse, 24, has 23 goals and eight assists over 83 MLS games (50 starts). The 24-year-old Williamson was handed his MLS debut a bit later than Ebobisse, but has appeared in all but two Timbers matches over the last two seasons.

Rejected transfer bids this winter, new contracts signed

Admittedly an oddly specific sub-group, but both players had bids rejected this winter before signing new contracts. Bids rejected from the same team, no less, after reigning Copa Libertadores champions Palmeiras sought to acquire both Eduard Atuesta and Valentin Castellanos.

The difference, though, is that Atuesta signed only a one-year extension whereas Castellanos inked a new five-year deal. LAFC reportedly set an asking price of $4 million for Atuesta over the offseason, which is not a steep fee for the Colombian defensive midfielder and 2019 MLS Best XI selection. The new bumper contract may change the math on that, though.

Atuesta, who turned 24 last week, remains every bit as important to LAFC's core as he was in their historic 2019 campaign. His quality and age are such that further overtures this summer should be no surprise.

Castellanos, meanwhile, is on his way to a career year for NYCFC, going from strength-to-strength after Palmeiras had multiple bids rejected. The 22-year-old has four goals and three assists in 10 games, as head coach Ronny Deila and sporting director David Lee have sung his praises while he held together an attacking unit as three key signings (Thiago Andrade, Talles Magno and Santi Rodriguez) awaited visas and travel to debut. Heber is also working his way back from injury. It was Castellanos' show and goals that paced them in the first two months of the season.

"I think it says they trust and believe the club will help them develop as players," Lee told MLSsoccer.com in May. "If you develop and your performance levels continue to develop, interest will come. It also means they both feel valued and wanted. If they didn’t think they would develop here, they wouldn’t have stayed. We’ve shown in the past that we understand our place in the football ecosystem. If interest and offers come for players who can improve their career and help the club, that’s a pathway we’re not opposed to. I think they know and trust we’ll work with the players to try and find solutions at the right times in their career.”

Maybe not yet but... soon?

That last quote above from Lee on Castellanos was also referring to James Sands, who also signed a new contract with NYCFC over the offseason. Like Castellanos, his deal was for five more years.

Sands was the first NYCFC academy player signed to a homegrown contract and has lived up to being the first through the door quite well. He proved himself a worthy first-teamer and then indispensable under three separate managers. He's being tracked by a number of European clubs.

The versatile defensive mid/center back turns 21 at the beginning of July and has been a key member of NYCFC's starting XI for three seasons. Only injuries (and a pandemic-shortened season) have limited him to 49 MLS appearances.

It seemed a foregone conclusion about a month ago that Justin Che would depart FC Dallas permanently before making his MLS debut, but the club and Bayern Munich didn't reach an agreement over the rising defender.

"Justin is a talented young player, and we expect him to have a very successful career," Jochen Sauer, head of Bayern campus, said via Steven Goff of The Washington Post. "He will remain a FC Dallas player in the near term."

Che spent the first half of 2021 on loan at Bayern Munich, starting with their U-19 side before quickly rising to Bayern Munich II in the German third tier. The US youth international, who also has a German passport, is a hugely rated talent. Prior to heading to Bayern on loan, he made 16 appearances in USL League One for North Texas SC in 2020.

He has since returned and made two starts with Dallas, providing a much-needed boost to an ailing defense. Che can play both center back and outside back.

Rapids midfielder Cole Bassett has made waves in MLS for a few seasons, as the 19-year-old has already racked up 49 appearances. He's set to continue as a nailed-on starter for Colorado while a number of players depart for international duty.

An energetic box-to-box midfielder, Bassett has had the valuable knack of scoring goals from deep in the midfield with late runs into the box. He already has 10 goals and eight assists in just over 3,000 minutes.

“I think Cole can be a national team player and can certainly play at a high level in Europe," Rapids GM & EVP Padraig Smith told MLSsoccer.com last year. "When you have a midfielder with the type of engine he has, the intelligence he has and the ability to contribute goals, that’s a potent combination. If he continues to do that in a consistent manner, it’ll take him right to the top.”

Freiburg have seen multiple bids rejected for Bassett, while Hoffenheim, Laussane-Sport and Rapid Vienna are among those interested.

Sam Vines, like his Colorado teammate, has also become an invaluable member of the squad. The homegrown left back has made 52 MLS appearances and three more with the United States. He'll be a key member of the Gold Cup squad.

Andrew Wiebe wrote about why he's excited to watch the 22-year-old this summer:

Vines was one of the US U-23s best players in a failed Olympic qualifying bid and already has three senior starts for Berhalter. He’s a 22-year-old who will hit 100 MLS starts this year, and the reason for that is he’s physically capable of keeping up with the game at the highest level and serves a wonderful ball, both early crosses and pushing to the endline.

Before the LA Galaxy fullback signed his MLS deal, Julian Araujo was reportedly in the sights of a few clubs abroad. More of the same is expected moving forward; he was even linked with Tottenham this winter.

The Mexican-American dual-national has earned his USMNT debut after being a regular at all youth levels. He impressed head coach Gregg Berhalter, though isn't on this summer's Gold Cup roster.

“Julian's an example of a guy that you want on your team,” Berhalter said in January. “He's a guy that goes out and puts everything on the line every time he's playing, and that's what we like about him. We see him as a fullback, and we want our fullbacks attacking, we want them to be aggressive. So I think he fits right into what we do. But we've been really excited about Julian, we really like his game, and we think it will translate well into what we do.”

The Canadian international and New England Revolution wide man is one to watch, with TSN's Matthew Scianitti reporting that a French and Dutch club have tabled multi-million offers for the player. He's been on the radar for a bit.

Buchanan can play on the wing or in a more defensive role, where he fits as a modern attacking fullback. A source told MLSsoccer.com that European clubs are particularly intrigued by him as a wingback or fullback.

The 22-year-old was selected by the Revs in the first round of the 2019 MLS SuperDraft and has made 44 MLS appearances, breaking out on the national stage with strong playoff performances last year.

The Real Salt Lake homegrown has been one of his club's most consistent players, a consistent starter since the middle of the 2018 season. Herrera is also adept at both right and left fullback, a useful trait.

Herrera already has 72 MLS starts to his name and the 24-year-old reportedly drew interest from Serie A last winter from Benevento, though they've since been relegated to Serie B.