La Liga president and UEFA Executive Committee member Javier Tebas said on Tuesday that Real Madrid, Barcelona and Juventus, the three clubs who have not officially resigned from the breakaway European Super League, should be "scared" of the outcome of UEFA's disciplinary proceedings against them.

Of the dozen clubs to form the new breakaway league outside UEFA's control, only Barcelona, Real Madrid and Juventus are still on board. The nine clubs who abandoned the proposal and settled with UEFA are: AC Milan, Inter Milan, Atletico Madrid, Arsenal, Liverpool, Manchester United, Tottenham, Chelsea and Manchester City.

Those clubs agreed to UEFA's terms to forfeit 5% of their prize money from European competitions in the 2022-23 season and pay a combined €15 million ($18.4 million) as a "gesture of goodwill'' to benefit children, youth and grassroots football.

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The three remaining clubs could face being banned from the Champions League by Europe's governing body.

"The ones that have to be scared are Real Madrid and Barcelona," Tebas said. "I don't want to imagine a Champions [League] without them but it can happen.

"More than a sanction, UEFA may opt not to register Madrid, and Barca in the Champions. I think they could be left out. They should be scared."

Barcelona's president pledged last week to go to the Court of Arbitration for Sport should UEFA make good on their threat.

"I told [UEFA president Aleksander] Ceferin that we were not going to apologise and that we were not going to pay a fine that is unjustifiable. If they fine us, we will go to the CAS,'' Joan Laporta said. "We will fight to protect the interests of Barcelona and to develop a model of football that is sustainable. All clubs are losing money.''

Tebas believes that measures have to be adopted to protect the current competitions.

"The idea of the Super League is a dream of [Real Madrid president] Florentino [Perez] for some time, it's not a COVID issue that they have tried to sell. The concept is not dead. They want everything to revolve around the big clubs and the others to be extras, to kneel down," he said.

UEFA gave no timetable for the expected disciplinary cases against the three, who have all qualified on merit for the Champions League next season.

The three clubs have begun legal action in a Madrid court against UEFA and FIFA. A judge has asked the European Court of Justice in Luxembourg to consider if restrictions on the rebel clubs are breaking European Union laws.

Tebas, meanwhile, spoke of Zinedine Zidane's decision to resign as Real Madrid coach and also commented on other potential arrivals to La Liga.

Zidane claimed he wasn't given the level of trust needed and criticised the club for "messages leaked to the media."

"I would prefer that Zidane remain in La Liga but if he is leaving, it is because he is unhappy at Madrid," he said. "I think he wants to continue to coach. I'm not surprised whatsoever by what he has said, Zidane about Florentino [Perez]. He has suffered due to well-placed leaks."

Tebas is hopeful that Paris Saint-Germain forward Kylian Mbappe will play in La Liga next season.

A target of Real Madrid, Mbappe has not signed a new contract with PSG, with his current deal expiring in June 2022.

Tebas believes Madrid must sell some players, including Gareth Bale, who played on loan at Tottenham this season and has one year left on his contract with Madrid, in order to land Mbappe.

"It would be good for La Liga that Mbappe plays in Spain," he said. "I. think Madrid could sign Mbappe, they can.

"[Gareth] Bale is the key to everything because of the salary level he has.

"That a team can bring Mbappe and [Borussia Dortmund star Erling] Haaland, I think it's impossible."

Tebas would like for Real Madrid captain Sergio Ramos to stay put. Ramos has not signed a contract extension and is a free agent this month.

"I would like for Ramos to stay but I don't know," he said.

Tebas is optimistic that Lionel Messi will remain at Barcelona beyond this summer. The Barcelona captain joined Argentina's squad without having signed a new contract at Barca and his current deal ending this summer.

"I believe he is going to stay," he said.

However, Tebas insisted that Barca must not bend the rules to keep the six-time Ballon d'Or winner.

"Nothing is going to be done for Messi to remain," Tebas said. "Rules are there for everyone to follow. We are not going to change the salary cap."