UEFA has opened disciplinary proceedings against Barcelona, Real Madrid and Juventus because of their part in the Super League project.
The Spanish and Italian clubs were among the 12 founding members of the competition intended to compete with the Champions League.
The majority of teams involved withdrew from the plot days after it was announced in April due to threats from football associations and protests from fans.
What has been said?
Barca, Madrid and Juventus have not said they will pull out, however, and UEFA announced this month that an investigation would be opened.