Gianluigi Buffon and Arjen Robben are among the players with their contract situations yet to be fully resolved ahead of the expiry of their current deals in the summer.
The Juventus goalkeeper was expected to leave the club and retire from the game at the end of the season when his contract runs out, though it is now unknown whether or not the 40-year-old will play on until next year.
Robben is hopeful of a short-term deal at Bayern Munich, though like Buffon is happy to walk away if an agreement cannot be reached.
Goal has the complete list of potential free agents from all of Europe's top clubs.
Arsenal's priority this summer will be extending the contract of Jack Wilshere.
The Gunners midfielder will see his current deal expire at the end of the season with no suggestion his demands will be met before he heads to the Russia World Cup with England.
Santi Cazorla's Arsenal career also looks set to end in the summer, with the Spaniard unable to recover from the heel injury which has kept him out of action since 2016.
Per Mertesacker's current deal will expire in the summer, though unlike Wilshere the German will not be looking for a new club; instead he will be taking a coaching role as academy manager.
Having secured contracts for Jose Gimenez, Gabi and Juanfran, Atletico Madrid are in a favourable position.
Fernando Torres, though, was only handed a 12-month deal last summer, with that deal set to expire once the current campaign comes to an end.
Bayern's list of out-of-contract players includes backup goalkeepers, a few young prospects and three first-team players in Arjen Robben, Franck Ribery and Rafinha.
That trio, all of whom are 32 or older, will likely see how the 2017-18 season ends before deciding whether or not to extend their terms by another year.
Roman Weidenfeller will retire at the end of the season, while fellow goalkeeper Dominik Reimann will also see his contract come to an end.
On-loan striker Michy Batshuayi will return to parent club Chelsea once the current season ends with a permanent deal looking increasingly unlikely.
Chelsea have three depth goalkeepers whose deals are up for renewal.
Willy Caballero and Eduardo could stay on as the second and third-choice options behind Thibaut Courtois but Matej Delac - who is Chelsea's longest-serving player despite spending barely any time at all in England - will move on due to his lack of a work permit.
Reserve goalkeeper Tommaso Berni looks set to leave the club, as does bit-part player Davide Santon.
Joao Cancelo, Rafinha and Lisandro Lopez will all return to their parent clubs, though the Serie A club may look to sign the players on a permanent basis in the summer.
Giorgio Chiellini looks set to extend his stay in Turin, telling Sky Sport Italia in February 2018: "We're going to renew my contract soon and there will be no surprises. We're close, but right now the management are too busy with the transfer market - next month we'll definitely get it done."
Gianluigi Buffon will decide whether or not to continue his career once the season has ended.
Kwadwo Asamoah and Stephan Lichtsteiner could also leave and Andrea Barzagli, 36, will have to make a decision on his future.
Emre Can has been linked with Juventus and his contract talks continue to drag on.
The German has made no secret of his desire to join a European giant and has frustrated Reds supporters as a result.
Fernandinho was awarded with a contract before the January transfer window, leaving just one senior player without a future at the club past the summer - Yaya Toure.
The Ivorian is yet to start a Premier League game for Pep Guardiola's Man City side this summer, registering just 97 minutes of league action, and will be free to leave the club in the coming months.
Manchester United triggered Ashley Young's one-year contract extension option this week following the England international's performances this season in similar fashion to that of Juan Mata in January and Ander Herrera in November 2017.
Marouane Fellaini does not look like he will be afforded the same deal, however, as he, Daley Blind and Luke Shaw fight to prove their worth before the end of the season.
Gabriel Paletta is unlikely to stay at Milan and Hachim Mastour looks to be struggling to live up to the billing he has been given as a young player.
Marco Storari could sign on again, though, despite being 41 years of age.
Joao Moutinho has been through all the ups and downs over the past four years at Monaco and though he is not as integral as he once was, he still provides an influx of creativity.
Whether that is enough to convince him to stay rather than returning to Portugal or moving elsewhere, though, remains to be seen.
Napoli will be keen to keep Pepe Reina, though the Spaniard looks set to complete a move to capital club AC Milan .
Christian Maggio and Rafael are both very much back up options for the Serie A side and will be allowed to leave in the summer once their deals are up.
|Hatem Ben Arfa||Forward|
Hatem Ben Arfa looks certain to leave having fallen out of favour completely under Unai Emery. When questioned on his situation in Paris, the former Newcastle and Nice winger said: "What I'm going through at PSG is very complicated, I have the feeling I don't exist."
Thiago Motta could end his seven-season spell in the French capital in the summer when his deal expires.
Real Madrid's young right-back Achraf Hakimi has broken into the first team this season and should be handed extended - and improved - terms before the end of the campaign.
Roma have only backup goalkeeper Bogdan Lobont to make a decision on.
Tottenham are another club with only their No.2 goalkeeper set to become a free agent unless he is tied down to an extension.