A leading sports lawyer has claimed that Lionel Messi should not leave Barcelona without resolving a dispute over his contract.

While Messi has formally requested an exit from Camp Nou, there is currently a disagreement with regards to a potential transfer fee for the superstar.

Barcelona are refuting Messi's efforts to depart on a free, reiterating that the option in question expired on June 10.

Although the issue threatens to derail the Argentine's attempts to find a new club, Nick De Marco QC has argued that Messi may have to be prepared to remain in Spain.

Speaking to Sky Sports News, he said: "If it ended up anywhere, it would be most likely in the FIFA Dispute Resolution Chamber because Messi, being Argentinian, the FIFA rules would apply, and FIFA has its own set of laws and rules. So, it's unlikely to be Spanish law or English law or Swiss law but it would be the FIFA rules that apply, and they have a commission that can determine these things.

"Ultimately, either party can then appeal to the Court of Arbitration for Sport. That's how these sorts of issues are normally dealt with. One possibility, and it's certainly not one I'm advising anybody, is a player simply just walks out and says, 'I'm entitled to walk out, so I'm walking out'.

"The risk with that strategy is, although FIFA will normally allow the registration to move with the player, if the club then brings a claim and succeeds, not only is the player liable to pay damages but also is likely to be banned under FIFA rules for a period of months and the new club signing him have a transfer embargo.

"It's such a high-risk strategy that, unless you were sure that the player was in the right, it's not a risk one would take."

Manchester City, Inter Milan, Paris Saint-Germain and Manchester United are all said to be monitoring the situation.