Lionel Messi can only leave Barcelona if his €700 million (£624m/$823m) release clause is met, La Liga 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 expired in June, but the Argentine's legal team are ready to argue that he should be allowed to terminate his deal unilaterally due to the 2019-20 season being extended into August because of the coronavirus pandemic.
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.
Paris-Saint Germain, Juventus and Manchester United are also thought to be considering a move for the six-time Ballon d'Or winner, but La Liga have now revealed their stance on his current situation.
Spanish football's main governing body have now said that the terms of Messi's current contract, which is due to run until 2021, remain valid, which means he will not be able to leave the club unless a potential suitor pays his €700m (£624m/$823m) buy-out clause in full.
An official statement on La Liga's website reads: "In relation to the different interpretations (some of them contradictory to each other) published in recent days in different media, related to the contractual situation of the player Lionel Messi with Barcelona, ​​La Liga considers it convenient to clarify [matters].
"The contract is currently in force and has a 'termination clause' applicable to the event that Lionel Messi decides to force the early unilateral termination of the contract.
"In compliance with the applicable regulations, and following the corresponding procedure in these cases, La Liga will not carry out the process for the player to be removed from the federation if they have not previously paid the amount of said clause."
Messi's battle to secure a move away from Barca is now threatening to become a drawn-out saga, even though he has already decided that he no longer wishes to play for the club.
The 33-year-old purposely failed to report for medical testing at the club's training facility ahead of the new season in order to put pay to any lingering doubts over his mindset.