Ferguson has been married to wife Cathy since 1966.
A statement from the League One club said: "Darren asks for privacy, and will provide an update through the club during the week".
Ferguson began his playing career with Scottish club Queen's Park as a 16-year-old striker while working as an apprentice tool-worker at Clyde Shipyards.
"He's probably the most iconic figure of football from the last 30 years, and then when you add that to the fact that he's such a important role model to so many people around the world, he's captured the world". He is a regular at horse racing meetings, has co-written two books, lectured internationally, attended the Oscars and watches the majority of United matches at Old Trafford, entertaining his guests in the directors' box before and after games.
His future at United was reportedly at stake when United travelled to Nottingham Forest for an FA Cup third-round tie in January 1990, but they won by a solitary goal.
He arrived at United from Aberdeen in 1986, having broken the stranglehold of Glasgow clubs Celtic and Rangers on Scottish football.
Ferguson can claim to have done it all, from winning in Europe with an unfashionable smaller club, lifting league titles in two different countries, collecting European silverware with two clubs and annexing trophies in four successive decades.
"Not surprised everyone has come out with these best wishes and we are all hoping for the best possible outcome for him". "I hope he has a full recovery".
Tiger Shoots Even Par In Return To Quail Hollow
He got another par on the drivable par-4 14th but there was no reason to celebrate as he missed his birdie chance from four feet. They feel springy, and they feel fast-especially as I'm walking on them, but they're not putting that way.
Aberdeen, the club he managed before his managerial move to England, sent its "thoughts and prayers" as did Tottenham Hotspur.
Mike Phelan, who was Ferguson's assistant for five years: You've won more than most and if anyone can, you can boss.
Departing Arsenal boss Arsene Wenger also expressed his best wishes to Sir Alex at the start of his farewell speech at the Emirates on Sunday afternoon after watching his side beat Burnley 5-0.
Edwin van der Sar: Devastated about the news about Sir Alex and knowing all too well about the situation ourselves.
Chris Smalling: Gutted to hear the news about Sir Alex.
The Scot had surgery to fit a pacemaker in 2004 after a heart irregularity was discovered and had a hip operation five years ago shortly after retiring from United.
Players past and present also showed their support to the former Manchester United boss who was at the helm of the Red Devils for 26 years.
But this weekend football fans worldwide are united in support for the former Manchester United boss as it emerged he had undergone emergency surgery for a brain haemorrhoid.
Ferguson, who is 76, has received thousands of well-wishes and tributes on social media, and the official Manchester United website has gathered all the kind messages from Fergie's former players.
Apple's Humongous Buybacks Went Into High Gear Last Quarter
The $US1,000 iPhone X - Apple's most expensive iPhone - was the best-selling phone "every week" during the quarter , Cook said. Wall Street analysts have praised the work Apple has put in to developing its other businesses away from the iPhone .
Has Israel acted appropriately at the Gaza border?
According to experts, the main goal of the President of the Palestinian national authority Mahmoud Abbas consolidate his power. But it has defended the shrinking permit numbers from Gaza, saying Hamas exploits travelers to smuggle money or weapons.
Matches to Make After Bellator 198
Meanwhile, Rafael Lovato Jr. locked in an armbar on Gerald Harris to get a victory a little over a minute into their bout. Putin has attended Emelianenko's fights, and the 41-year-old fighter has been photographed with the Russian president.
James Comey book sells more than 600000 copies in first week
I write at the end of my book that Trump's presidency is a forest fire ... they do damage but things grow in the wake of them. Higher-than-expected demand led Macmillan imprint Henry Holt & Co to order up 2.1 million copies in its first week.
Amazon to employ 3000 people at new Vancouver facility
The construction of this new facility is expected to generate additional funding for job training programs in Boston. The technology giant is expanding its team focused on Alexa and Audible, opening an office in Boston's Seaport.