Manchester United's executive vice chairman, Ed Woodward has resigned.
It follows the news Manchester City has begun to formally withdraw from the from the Super League after a huge backlash by fans and players.
It is unclear if Woodward's resignation affects United's standing within the league.
Woodward will step down from his role at the end of 2021 and, in a statement says it had been "an honour to work for the world's greatest football club for the past 16 years".
He continued: "The club is well positioned for the future and it will be difficult to walk away at the end of the year."
After the announcement United co-chairman Joel Glazer said: "Ed Woodward has served the club with great distinction.
"On behalf of everyone at United I would like to place on record our sincere thanks for his tireless work and dedication.
"His contribution to the club has been massive, and he will always be welcome at Old Trafford as a part of the Manchester United family."
49-year-old Woodward took the post at Old Trafford in 2013 and played a key role in creating the Super League.
It is understood his resignation was amicable with the owners and reportedly unrelated to the Super League.
In a statement confirming his resignation Woodward said:
"I will treasure the memories from my time at Old Trafford, during a period when we won the Europa League, the FA Cup and the EFL Cup.
"I am proud of the regeneration of the club's culture and our return to the Manchester United way of playing.
"We have invested more than £1bn in the squad during my time here and I am particularly delighted with the progress the players have made under the astute leadership of Ole Gunnar Solskjaer and his coaching team in the last two years.
"I am sure that with the changes we have made on-field and to the coaching and football staff in recent years this great club will soon be lifting silverware again. It deserves to.
I desperately wanted the club to win the Premier League during my tenure and I am certain the foundations are in place for us to win it back for our passionate fans.
"Our world-famous academy is flourishing again, with 34 players progressing into the first team since 2013, and it has been a pleasure to watch talents such as Marcus Rashford, Mason Greenwood and Axel Tuanzebe flourish in the first team environment.
"In the years to come the club's production line of young talent will continue to push established first team players for their places. That competition bodes well for the future.
"We have also established Manchester United women and their progress is further evidence of the demand for success at this great club.
"The last 16 months have brought so many unique challenges and the club's work in the community and around the world during the Covid-19 pandemic has been heroic."
The news has come less than 48 hours after the proposals were made public, which would see six English teams form a 12-strong European league, including teams from Spain and Italy.
Which teams are involved in the European Super League?
England: Arsenal, Manchester City, Manchester United, Chelsea and Tottenham
Spain: Real Madrid, Barcelona and Atletico Madrid
Italy: Inter Milan, AC Milan and Juventus
The controversial plans sparked widespread criticism when they were announced on Sunday 18 April.
Fans from all teams appeared united in their opposition, and said they felt the move was based on financial gain and "represents the death of everything that football should be about".
Managers from the teams also voiced their opposition including Liverpool manager Jürgen Klopp, who criticised the plan but defended the club following a monumental backlash.
Following their 1-1 draw with Leeds on Monday 19 April the Reds boss said: "The team has nothing to do with it.” He said the club has been through tough times before and that he would not resign but would try to help "sort it" despite not agreeing with the move.
Liverpool captain Jordan Henderson also voiced his opposition on his Twitter account - his statement was quickly retweeted by other members of his team.
Manchester City manager Pep Guardiola said: “It is not a sport where the relation between effort and success does not exist.
"It is not a sport where success is already guaranteed, it is not a sport where it doesn’t matter when you lose.”
Manchester City midfielder Kevin De Bruyne also voiced his concerns of the European Super League on social media.
He posted a picture of a statement on Twitter: “This man comes out a little town out of Belgium dreaming of playing at the highest stage possible. I’ve represented the Belgium, German and English league. And also proudly represented my country.
“I have worked and competed against everybody trying to win the ultimate. But the most important word in this is COMPETING."
Manchester United is the only North West team not have commented publicly on the matter in any form - but United and England striker Marcus Rashford shared an image on Twitter of one of the banners which covers the stands at Old Trafford.
What exactly is being proposed?
The plan – which also includes the Spanish sides Atletico Madrid, Real Madrid and Barcelona and Italian clubs AC Milan, Juventus and Inter Milan – has support from investment bank JP Morgan, which will provide debt financing for the competition.
It is understood it will underwrite around $6billion (£4.3 billion) in loans for teams involved.
It would see the breakaway teams create a competition to rival the Champions League, but it would not feature relegation or promotion.
Teams would play each other in midweek while still competing in their domestic leagues.
In the fallout from Sunday's announcement, Boris Johnson has threatened to "drop a legislative bomb" on the breakaway league.
The PM told a round table discussion on the issue that the government "will not stand by while a small handful of owners create a closed shop", and suggested new laws could be brought in to block the breakaway competition."
He reiterated his unwavering support for the football authorities and confirmed they have the government’s full backing to take whatever action necessary to put a stop to these plans," Number 10 said.
"He was clear that no action is off the table and the government is exploring every possibility, including legislative options, to ensure these proposals are stopped."