Lionel Messi and Sergio Aguero among 23 big-name free transfers this summer

Just a few months remain on the contracts of a host of stars, including the Barcelona and Manchester City hot shots. See the slideshow below

Lionel Messi: The Barcelona star almost left the Camp Nou last summer, and the whole saga could reignite again at the end of this season when his current deal runs out. Will the world's best player remain a one-club man, or will he dip his twinkle toes in the Premier League? Getty Images

Sergio Aguero: The 32-year-old is the most prolific foreign striker in Premier League history but has endured an injury-hit past year. He has said he's not sure what his future holds and City may turn their attention to Erling Haaland, Harry Kane or even Lionel Messi this summer. EPA

Sergio Ramos: The Real Madrid talisman's contract situation has dominated headlines in Spain for some time. Not quite the Messi saga, but will cause a major ripple if the 34-year-old does depart the Spanish capital this summer. He wouldn't be short of offers. Reuters

David Alaba: The super-successful Bayern Munich defender has confirmed he is leaving this summer, but where is he going? Europe's elite are vying for his signature. Getty Images

Memphis Depay: The Dutchman has revived his career at Lyon after a disappointing spell at Manchester United. Now could be his chance to get a move back to one of the world's biggest clubs, and possibly back to the Premier League, though Lyon are hopeful he will stay with 14 league goals bagged so far this season. AFP

Gianluigi Donnarumma: The Milan goalkeeper is a veteran of more than 200 games, yet is still only 22 years old. His agent, Mino Raiola, was reported in Italy as saying he wants a two-year deal making Donnarumma the second highest-paid keeper in the world behind David De Gea, but Milan want a three-year deal. Getty Images

Luka Modric: The Ballon d'Or winner would leave a big hole in the Real Madrid midfield should he depart. However, at 35 and on hefty wages, Real could look to reduce their wage bill amid the pandemic. EPA

Georginio Wijnaldum: A Premier League and Champions League winner at Liverpool, but yet to agree a new deal. The midfielder has been heavily linked with a move to Europe's wealthier clubs such as PSG and Barcelona. He may fancy a fresh start with Liverpool stuttering this season. Reuters

Juan Mata: The veteran's time on the pitch has dwindled in recent years. Manchester United have an option to extend the Spaniard's deal for another year and manager Solskjaer said there will be interest as "one, he’s a very good footballer; two, he’s a fantastic professional and human being". Getty Images

Danny Rose: Frozen out at Tottenham under Jose Mourinho, the left-back looked set for a move to Trabzonspur in Turkey during January but that fell through. The 30-year-old should have a few seasons at the top level left in him. Getty Images

Julian Draxler: The PSG midfielder's opportunities have been limited in recent seasons. "He is a player who is still important for the club," said manager Leonardo an interview with France Bleu Paris. A move may see him become the player many expected him to be. Reuters

Christian Benteke: One of a host of Crystal Palace players out of contract this summer. The striker endured three barren years in front of goal but has netted four league goals this season, including a last minute winner against Brighton last week. AFP

Patrick van Aanholt: Arguably the most sought-after of Palace's out-of-contract players. On his day he can be a firecracker of a full-back. Getty Images

Andros Townsend: The Crystal Palace winger, like Benteke, is waiting on his future. Manager Roy Hodgson says "sometimes not a good thing if you - very early on - let players know that you don't want them anymore at the time we are depending so heavily on them". Getty Images

Jerome Boateng: A regular in the Bayern Munich defence this season, but now 32 and the club has a history of not offering more than one-year deals to older players. Reuters

Edinson Cavani: The 34-year-old has impressed since his switch from PSG to Manchester United, netting six Premier League goals so far. Manager Ole Gunnar Solskjaer has confirmed talks will take place over extending his stay. AP

Fabian Schar: Has he played his last game for Newcastle? The Swiss defender is out injured for a few months but hopes to be fit for the European Championship in the summer. PA Wire.

Lucas Vazquez: Now in his sixth season in the Real Madrid first team, the Spaniard has played regularly this term at either full back or on the wing. Contract talks rumble on. AFP

Henrikh Mkhitaryan: Now 32, the Armenian has been in fine form for Roma this season with 9 league goals and 9 assists in Serie A. He is represented by Mino Raiola who is often quick to talk up moves for his clients. Getty Images

Angel Di Maria: The PSG winger has had a productive season so far with four goals and 9 assists. He recently encouraged fellow Argentine Lionel Messi to join him in France. AFP

Florian Thauvin: The Marseille star continues to impress in France after his disappointing spell in England with Newcastle. He took to Twitter to laugh off reports that Real Madrid had turned down the chance to sign him. AFP

Hakan Calhanoglu: AC Milan's Turkish attacker has been linked with Manchester United and will face them in the next round of the Europa League. Reuters

David Luiz: There's talk of a player-coach role at Arsenal if he stays on, though his performances continue to be inconsistent. AFP

As football clubs grapple with tightened budgets amid the coronavirus pandemic, focus is set to sharpen on the players available on free transfers this summer.

There's one name above all else which is set to gain the most attention should he not be tied down to a new contract - and that is Lionel Messi.

The Argentine superstar's position at Barcelona looks set to be the drama of the summer once again following on from part 1 last year in what was a saga surely worthy of a Netflix series.

Will he stay, or will he go? And if he does go, who can afford him?

Messi and Ramos the talk of Spain

But Messi isn't the only big name player out of contract this summer.

Elsewhere in Spain, talk of Sergio Ramos's future has taken centre stage in Madrid.

The 34-year-old is almost part of the furniture at Real, but terms on a new deal are yet to be agreed and he has been free to talk to other clubs.

And it could be all change at the Bernabeu if Luka Modric and Lucas Vazquez also move on.

Will Aguero stay at Manchester City?

Teams seeking a goal boost will be keeping an eye on Sergio Aguero's situation at Manchester City.

He's had fitness problems this season and is yet to open his Premier League account, however he was back in action during City's victory over West Ham at the weekend, which made it 20 wins in a row for Pep Guardiola's side.

Fellow Premier League side Liverpool are yet to agree a deal with Giorginio Wijnaldum, while Juan Mata's spell at Manchester United could be coming to an end.

See the full list below and in the slideshow at the top.

Out of contract players, June 2021

• Lionel Messi, Barcelona
• Gianluigi Donnarumma, AC Milan
• David Alaba, Bayern Munich
• Sergio Aguero, Manchester City
• Sergio Ramos, Real Madrid
• Memphis Depay, Lyon
• Georginio Wijnaldum, Liverpool
• Hakan Calhanoglu, AC Milan
• Florian Thauvin, Marseille
• Angel Di Maria, PSG
• Henrikh Mkhitaryan, Roma
• Lucas Vazquez, Real Madrid
• Fabian Schar, Newcastle
• Edinson Cavani, Manchester United
• Jerome Boateng, Bayern Munich
• Luka Modric, Real Madrid
• Christian Benteke, Crystal Palace
• Andros Townsend, Crystal Palace
• Patrick Van Aanholt, Crystal Palace
• Juan Mata, Manchester United
• David Luiz, Arsenal
• Danny Rose, Tottenham
• Julian Draxler, PSG