Winds of change seem to be blowing at Old Trafford ever since their 'noisy neighbours' Manchester City pipped them to the Premier League title.
The calls have grown increasingly strident ever since Sir Alex Ferguson suffered a health scare last week.
Ferguson was taken to hospital by ambulance after suffering a nosebleed that would not stop before he was due to speak at a dinner in Glasgow.
It was a wake-up call not only for Ferguson but the club management who have considered taboo until now to talk of a successor to the legendary Scot.
They are bracing for the inevitable after Ferguson's old friend Dave Whelan claimed that the Manchester United boss will quit at the end of next season, according to the Daily Mail.
Ferguson predicted that he would stay on for another three years when he turned 70 on New Year’s Eve, but said health will be the deciding factor.
Whelan believes the Scot will retire in 12 months because the pressure is taking its toll.
The Wigan chairman said: "After next season, Sir Alex will call it a day.
"The pressure is telling, especially when you’re at the top for so long.
"He had a little scare and that tells me he will think very hard and realise there is no point trying to carry on and take the risk."
So now is the ideal time to be talking about Ferguson’s retirement from United.
It has often been halted in its tracks by the lack of a clear replacement.
One who can continue the Scot’s “winning mentality”, but still play the free-flowing football associated with United.
Perhaps for the first time, a candidate is available.
In all the myriad roles that the media have speculated Pep Guardiola being associated with after Barcelona, Manchester United has never been among them.
Yet, if United are looking for a winner with the DNA of Sir Alex, strangely, Guardiola would be the one.
He has the mentality, he plays the football, he knows the pressure, he is available.
Sir Alex has been at United over 20 years. Manchester City have brought a new change in the Premier League.
Perhaps it is time for a change at Old Trafford.
Instead of the hair-dryer, perhaps it’s time for a Pep talk.
Jose Mourinho agreed to extend his contract with Real Madrid for two years on Tuesday, ruling him out of a sensational return to Chelsea.
The 49-year-old Portuguese coach led Madrid to its first Spanish league title in four years this season to add to the Copa del Rey trophy he won during his first campaign at the Santiago Bernabeu.
Under Mourinho's guidance, Madrid set both the league scoring record with 121 goals and the points record with 100 en route to its 32nd championship title this season.
He has been tied to the club until the end of the 2015-16 season after penning an initial four-year deal when he took over at Madrid in May 2010.
The news will put an to end speculation about Mourinho's future, with reports still linking him with the vacant managerial position at former club Chelsea.
However, it could be master stroke by the 'Special One' not to jeopardise his chances of eventually replacing Sir Alex Ferguson at Manchester United.
Mourinho got an endorsement that he is the natural successor to Ferguson by Cristiano Ronaldo who has achieved the distinction of playing under both.
"Ferguson was like a father to me, he taught me many things, and I achieved a very nice part of my career with him. Mou, for his part, is the best coach in the world and to be with him now is great to be able to continue growing, it's very good working with him because he's the No 1," said Ronaldo during an interview with newspaper AS when pressed for comparisons.
Mourinho for his part is still hungry for success despite being one of only three coaches to have won the Champions League with separate teams having led Porto to the crown in 2004 and Inter in 2010.
He said: "As a manager, I always try to grow and improve. I've loved the professional experience I've had of working for different clubs in different countries and cultures, and to learn from that while giving my best. I've loved that process.
"It's different for me now because I'm thinking about a club long term, and that club is Real Madrid, which has been more demanding and has forced me to do my absolute best due to its difficulties.
"I've had to improve as a coach and a professional. I think it is the perfect challenge for the next four years because you always have to do more when things are hardest. I need these great challenges in the maturity of my career; I need things to force me to be better."
United can rest assured Mourinho is just biding his time to move to Old Trafford at the opportune time.