Lionel Messi, Isco, Andres Iniesta and Arjen Robben among stars to be out of contract next summer

Lionel Messi, Isco, Andres Iniesta and Arjen Robben are among a host of stars that could be available on a free transfer next summer.

Arsenal face the possibility of losing Alexis Sanchez and Mesut Ozil when their contracts expire in July - but there could be plenty of free replacements available.

We evaluate the top players with expiring contracts in each position, according to transfermarkt.co.uk data...

GOALKEEPER

Gianluigi Buffon could be available on a free transfer next July

Gianluigi Buffon is the most high-profile stopper available on a free if his current Juventus contract expires next summer - but the Italian is "99.9 per cent" certain he will retire from football after the 2018 World Cup.

Former Liverpool stopper Pepe Reina could also be a free agent when his Napoli deal expires in July, having been linked with a move to Newcastle during the recent transfer window.

Everton's Joel Robles could also be available, having made an impressive run of starts last season before Ronald Koeman signed Jordan Pickford.

CENTRE-BACK

Juventus defender Giorgio Chiellini could leave on a free transfer next summer

Juventus and Italy centre-back Giorgio Chiellini is the biggest name on the out-of-contract list of centre-backs, while young prospects Jose Gimenez (Atletico Madrid) and Stefan de Vrij (Lazio) could be coveted free targets.

Per Mertesacker is set to hang up his boots and assume a coaching role at Arsenal, while familiar names of potential free agents include Steven Caulker (QPR) and Robert Huth (Leicester).

Meanwhile, Florentin Pogba could join brother Paul in the Premier League when his St Etienne contract expires.

LEFT-BACK

Patrice Evra's contract at Marseille expires in July

Manchester United duo Daley Blind and Luke Shaw top the list of most desirable free agent left-backs - but United have confirmed one-year extension options on both players.

Former United full-back Patrice Evra could make a return to the Premier League, having just 10 months remaining on his current Marseille deal, while Burnley's Stephen Ward could also be a free agent.

Reina's Napoli team-mate Faouzi Ghoulam is a highly-rated potential free transfer, while Watford's Jose Holebas could also be on the radar of several clubs.

RIGHT-BACK

Experienced Atletico Madrid defender Juanfran is out of contract in July, as are Rafinha (Bayern Munich), Glen Johnson (Stoke) and Joel Ward (Crystal Palace).

CENTRAL MIDFIELD

Isco is reportedly set to sign a new contract at Real Madrid

A host of world-class central midfielders could be available on a free transfer next summer, including the likes of Mesut Ozil (Arsenal), Andres Iniesta (Barcelona), Leon Goretzka (Schalke) and Isco, who is reportedly set to sign a new contract with Real Madrid.

In addition to those star-studded options, alternative big names with expiring deals include Ross Barkley (Everton), Fernandinho, Yaya Toure (both Man City), Jack Wilshere, Santi Cazorla (both Arsenal) and Emre Can (Liverpool).

Elsewhere, Yohan Cabaye (Crystal Palace), Max Meyer (Schalke) and Hatem Ben Arfa (PSG) could also be free agents.

Manchester United midfielders Ander Herrera, Juan Mata and Marouane Fellaini all have contracts set to expire in July - but United have one-year extension options on Herrera and Mata.

LEFT MIDFIELD/ WING

Alexis Sanchez looks set to leave Arsenal on a free transfer next summer

Arsenal's Alexis Sanchez only has 10 months left on his contract, having failed to complete a move to Manchester City after would-be replacement Monaco winger Thomas Lemar reportedly turned down a transfer to the Emirates.

Bayern Munich attacker Franck Ribery could also make a swansong switch away from the Bundesliga when his contract expires next summer.

RIGHT MIDFIELD/ WING

Lionel Messi only has 10 months remaining on his current deal at Barcelona

Lionel Messi would be the undisputed all-time bargain - if the Argentinian was prised from Barcelona on a free transfer next summer.

Despite being widely regarded as the world's best player, Messi only has 10 months left on his current deal at the Nou Camp.

Former Chelsea and Real Madrid winger Arjen Robben has also entered his final year at Bayern Munich, as has Aaron Lennon (Everton) and Chung-Yong Lee (Crystal Palace).

STRIKER

Atletico Madrid striker Fernando Torres could be a free agent in July

In terms of strikers on potential free deals, Mario Balotelli (Nice), Fernando Torres (Atletico Madrid) and Zlatan Ibrahimovic (Manchester United) are the headliners.

Other familiar names include Diafra Sakho (West Ham), Abel Hernandez (Hull City), Mame Diouf (Stoke City) and Tomer Hemed (Brighton).