Lionel Messi can only leave Barcelona if his €700 million (£624m/$823m) release clause is met, La Liga have confirmed on Sunday.
Messi handed in a transfer request to the Barca board last week, with a view to triggering the clause in his contract which allows him to leave the club at the end of each season.
The clause in question technically expired in June, but the Argentine's legal team are ready to argue that he should be allowed to terminate his deal unilaterally.
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Manchester City is thought to be the most likely next destination for Messi, with Goal reporting that ex-Barca boss Pep Guardiola has been in touch over a potential reunion at Etihad Stadium.