La Liga president Javier Tebas has warned Barcelona that they cannot force Frenkie de Jong to take a pay cut.
Barça have been undergoing a programme of 'economic levers' this summer as they attempt to steady the ship financially.
This has included selling a percentage of their La Liga television rights and signing a lucrative sponsorship deal with Spotify.
Despite these measures, reports have suggested that Barcelona may still struggle to register new signings Robert Lewandowski and Raphinha. As a result, they have been exploring the option of cutting De Jong's wages - who previously had already agreed to defer over £17m of his earnings.
However, Tebas warned that this would not be permitted by La Liga.
"The players cannot be split from the team or pressured - it’s what collective agreement, the law, reason, ethics say," Tebas said via Sport.
"From there, Barcelona knows the rules and the responsibilities."
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De Jong has been strongly linked with a move to Man Utd this summer, and 90min understands that the two clubs have a broad agreement in place. However, the issue of the Dutchman's deferred wages and the midfielder's desire to remain at Camp Nou is causing the deal to stall.
Tebas was also quizzed about whether he thought Barça would be able to register their new signings, even if De Jong is not sold.
"They know what they have to do - I think that they still have a bit of work to do but they are on the right track," he added.
"Ask FC Barcelona. I can say that they know the rules well and they are well aware of what they have to do. They still need to do it, but there is still some time.
"They have sold 10 per cent of their TV rights for €207m. Then they increased that share to 25% which I think gives them some €350m more.
"That would be €500m and I think they have another, third lever that of around €200m. With that and if they manage to get some players to leave, this explains the possibility of these signings.
"They have been able to sell assets, which was something they needed to do, and to reduce salaries – that’s what allows them to sign."