Ed Woodward has resigned as Manchester United executive vice-chairman, the PA news agency understands.
The 49-year-old took the post at Old Trafford in 2013 and played a key role in the now stuttering Super League.
It is understood he will continue in his role with United until the end of 2021.
It comes amid the news that Chelsea are preparing to withdraw from the proposed competition.
Owner Roman Abramovich is understood to have driven the decision, having listened to fan protests and opted to withdraw from the new European league plans.
Chelsea have become the first of England’s ‘Big Six’ clubs to choose to quit the competition, which was only announced on Sunday night.
Brighton boss Graham Potter said Chelsea’s decision was “fantastic news”.
“We’re very pleased,” he told. “We feel it stands against everything we know as football. It would be wrong to create something where there is no threat of relegation and you want the chance to compete to play in Europe.
“If we are in a place where it is stopping, that is fantastic news. Sometimes a fan can be thought of as a consumer and we are in danger if that is the case.”
The Seagulls’ coach was delayed by the mass protests outside the ground.
Potter added: “Credit to the fans for making their case, and the quicker we get back to playing for points the better. We were a little bit delayed but the supporters are the most important thing.”
Meanwhile, there are reports that Manchester City and Barcelona are also preparing to officially withdraw from the competition.
City would not comment on reports they could withdraw from the breakaway competition when approached by the PA news agency.
A club spokesperson said: “We cannot comment for legal reasons.”