As we head into another summer of transfer activity we take a look at some of those stars most vulnerable to bids from rival clubs: the players who have just one year remaining on their current contract.
This will be the last chance for their clubs to earn maximum profit on any wantaway stars or they risk losing them for nothing next summer.
2020 will be a big summer for out-of-contract players (assuming their futures aren't sorted out before then of course), here's a starting XI for those deals that are set to expire in 12 months' time.
1. GK - David de Gea - Manchester United
His stock has dropped a little since an equally embarrassing World Cup, but the Spaniard is still one of the best shot stoppers in the world.
The latest gossip says United are no closer to agreeing an extension for the keeper. Real Madrid have been a firm admirer of the 28-year-old for some time and could reignite their interest after Thibaud Courtois struggled to find his feet since his switch to the Santiago Bernabeu.
2. RB - Thomas Meunier - PSG
The Belgian hasn't stolen many headlines in his career but he is a top class attacking full back, which is an increasingly significant role in the modern game.
He has even been deployed as a right winger by international manager Roberto Martinez where, as England fans may remember, he scored the opening goal in the World Cup third-place play off game.
3. CB - Toby Alderweireld - Tottenham
Meunier's international team mate Toby Alderweireld is also out of contract next summer as Tottenham fans will be very aware. The Belgian has formed a key part of Mauricio Pochettino's defence over the past four seasons.
At 30, he appears to have become disillusioned with the club's prospects and has been linked with a switch to Manchester United for some time. That could still come off this summer though following the events of last season, he may reconsider.
4. CB - Stefan Savic - Atletico Madrid
Stefan Savic may be remembered as a flop to Manchester City fans but he has firmly proved himself on the continent since leaving the Premier League. He established himself as a top defender in Serie A, earning him a switch to Atletico Madrid.
At Atletico, he became the first Montenegrin to play in the Champions League for the best part of two decades, helping guide them to the final, before lifting the Europa League with them two years later.
5. LB - Ryan Sessegnon - Fulham
Ryan Sessegnon is one the most exciting young talents in the UK at the moment after two breakthrough campaigns, where he helped Fulham earn promotion in 2018. He has been moved up to a winger role but is a left back by trade and could slot back into that role at a larger club.
After Fulham failed to secure Premier League survival in their first season, the 19-year-old is expected to depart the London club with Tottenham reportedly confident of securing his services this summer.
6. CM - Luka Modric - Real Madrid
Luka Modric is the oldest player on this list and will be 34 by the time his current contract expires. After winning his first Ballon d'Or this year though, it's hard not to include the Croatian playmaker as one of the best available options.
Recent reports suggest that Modric will get an extension to his current contract, so he is still likely to remain at the Bernabeu. Until he signs on the dotted line though, anything can happen.
7. CM - Ilkay Gundogan - Manchester City
Ilkay Gundogan has rarely stolen the show during his time at Manchester City but he has quietly become a vital cog in Pep Guardiola's dominant side. Fernandinho often gets the majority of the credit for making that midfield tick, but the German is more than worth his starting place in one of the best Premier League sides of all time.
He made 41 appearances last season as his side completed a clean sweep of domestic honours, but is reportedly unsure of his future with a return to Germany mooted.
8. RW - Willian - Chelsea
The Brazilian is possibly one of the most underrated stars in the Premier League. He's been consistently brilliant throughout his six years a Chelsea. He perhaps shone the most during Chelsea's disastrous 2015/16 campaign where they were let down by so many of their big name stars.
Willian played a vital role in Chelsea's last two most recent title-winning seasons and he won't find himself short of suitors if the Blues decide to cash in on the 30-year-old.
9. AM - Christian Eriksen - Tottenham
Other than Harry Kane, Christian Eriksen is Tottenham's most important player and unfortunately, like his teammate Alderweireld, he appears to be eyeing an exit. There was a time when Spurs were the best side in the league over a three-season period, but they failed to lift any silverware during those campaigns.
Having since been well overtaken by Manchester City and Liverpool the moment looks to have passed and stars like Eriksen are considering their options.
Spurs still have a Champions League final to play that could change some minds, but Real Madrid are believed to have made the Dane a top priority this summer.
10. LW - Eden Hazard - Chelsea
Without a doubt the most high-profile name on this list with an estimated market value of around £135m, even with just a year left on his contract. Eden Hazard can play in a variety of attacking roles and has been Chelsea's talisman for the past seven years.
He finished as top scorer again in the previous campaign with 19 goals in all competitions and he could have put himself in the shop window for summer. Real Madrid have also made Hazard a priority as they look for a big summer rebuild after a torrid campaign that was on par with their worst of all time.
11. ST - Timo Werner - RB Leipzig
The 23-year-old is one of the hottest properties in world football after playing a significant role in the meteoric rise of RB Leipzig. He already has 63 Bundesliga goals to his name and is expected to become the future of the Germany national team.
Timo Werner has shown the potential to develop into a world class striker which has attracted the attention of several top European clubs. Bayern Munich are unsurprisingly rumoured to be considering a move for the German, while Liverpool are also long-term admirers.
Substitutes: Marcus Rashford (Manchester United), Dries Mertens (Napoli), Stephan El Shaawary (AS Roma), Nabil Fekir (Olympique Lyonnais), Jan Vertonghen (Tottenham), Layvin Kurzawa (PSG), Keylor Navas (Real Madrid)