The three clubs are the only teams of the original 12 Super League clubs who signed up for the breakaway competition not to have formally renounced the competition and renewed their commitments to UEFA.
The trio could be expelled from the Champions League for two years as a consequence.
UEFA released a statement on Wednesday which read: ‘In accordance with Article 31(4) of the UEFA Disciplinary Regulations, UEFA Ethics, and Disciplinary Inspectors have today been appointed to conduct a disciplinary investigation regarding a potential violation of UEFA’s legal framework by Real Madrid CF, FC Barcelona and Juventus FC in connection with the so-called ‘Super League’ project.
‘Further information regarding this matter will be made available in due course.’
The two-year ban from Europe’s leading club competition is the harshest sanction at UEFA’s disposal.
The prospect of disciplinary action appeared inevitable last Friday when a statement confirming the peace accord with nine of the clubs ended: “UEFA has reserved all rights to take whatever action it deems appropriate against those clubs that have so far refused to renounce the so-called ‘Super League’.
“The matter will promptly be referred to the competent UEFA disciplinary bodies.”
The nine other clubs including the Premier League’s ‘big six’ ( Manchester United, Manchester City, Arsenal, Chelsea, Liverpool, and Tottenham Hotspur) committed themselves to UEFA competitions over threat of heavy fines and expulsion if there was any renewed attempt by any one of them to break away.
However, Real, Barca, and Juve issued a joint statement on Saturday standing by the Super League project, stating it was lawful and that it would be “highly irresponsible” of them not to continue to look at ways to answer what they see as the “existential questions which threaten football”.
Real Madrid president Florentino Perez was announced as the chairman of the Super League in the statement confirming its foundation.
His Juventus counterpart, Andrea Agnelli, resigned from his position on UEFA’s executive committee and his chairmanship of the European Club Association in order to sign up to the project.
He became a vice-chairman of the league, which collapsed within 72 hours when the English clubs withdrew amid fan protests, Government pressure, and managerial staff.
Manchester United’s co-chairman, Joel Glazer was also a vice-chairman of the ESL.
His family have committed to paying United’s share of a 15million euros ‘goodwill contribution’ as part of the club’s reintegration to the UEFA fold, and to covering the five percent of competition revenue which will be withheld from the nine clubs next season.