Ed Woodward has stepped down as executive vice chairman of Manchester United, Sky News understands.
The move comes amid fury at plans to create a European Super League featuring six English teams, including Manchester United, and other top clubs from Spain and Italy.
Mr Woodward, 49, took the post at Old Trafford in 2013 and played a key role in the now stuttering league.
It is understood he will continue in his role with United until the end of 2021.
Mr Woodward had already agreed to leave his role at the end of this year, but the announcement has been brought forward amid the Super League backlash, according to Sky Sports News.
Shares in Man United fell following the news as the New York Stock Exchange headed for closing on Tuesday.
The club is yet to announce whether it will join Manchester City and Chelsea in pulling out of the Super League.
A spokesperson said it “could not comment for legal reasons”.
United have been one of the leading clubs involved in the breakaway project, with Mr Woodward singled out for criticism by the head of UEFA Aleksander Ceferin.
Chelsea are preparing documents to formally withdraw, it was reported on Tuesday, and owner Roman Abramovich is understood to have driven the decision, having listened to fan protests and opted to back out.
Man City have told organisers that they do not wish to be a part of the planned new league.
It leaves just Manchester United, Liverpool, Arsenal and Tottenham, along with the six European clubs, Atletico, Real Madrid, Barcelona, AC, Inter Milan and Juventus.
Juventus has been forced to deny that chairman Andrea Agnelli, one of the brains behind the Super League, is also planning on resigning.
Players, pundits and politicians praised Man City and Chelsea for their decision.
Prime Minister Boris Johnson tweeted: “The decision by Chelsea and Manchester City is – if confirmed – absolutely the right one and I commend them for it. I hope the other clubs involved in the European Super League will follow their lead.”
Culture Secretary Oliver Dowden added: “Good news that Chelsea and City have seen sense, and I urge the rest to follow swiftly.
“The whole ESL move shows how out-of-touch these owners are. They have completely misjudged the strength of feeling from fans, players and the whole country. Football is for the fans.”