This Thursday, UEFA announced that it has launched an investigation into Barcelona for a "potential violation of its legal framework" in relation to the so-called 'Negreira Case', which is being investigated by the Spanish courts. Pursuant to article 31 (4) of the Ethics and Disciplinary Regulations, UEFA confirmed that it has appointed disciplinary inspectors to conduct the same.
The UEFA statement that is already posted on their website states, "In accordance with Article 31(4) of the UEFA Disciplinary Regulations, UEFA Ethics and Disciplinary Inspectors have been appointed today to carry out an investigation into a possible breach of UEFA's legal framework by FC Barcelona in relation to the so-called 'Negreira Case'".
So with the entry of UEFA in the 'Negreira Case', possible sanctions are already considered in the event that it is determined that these practices go against the cleanliness of football. Barcelona could be excluded from all European competitions for a certain time if it is finally concluded that there has been a 'violation' of the laws. Although qualification for the Champions League, the Europa League or the Conference League is established by the results in the national leagues, UEFA have the power at all times to prevent any club from playing in its competitions if it deems so, even if they have qualified based on their position in the domestic competition.