Sir Alex Ferguson is recovering after an emergency surgery for a brain haemorrhage.
His former club Manchester United have announced the procedure has gone "very well" but he needs a period of intensive care to optimise his recovery.
Ferguson's son Darren, manager of League One side Doncaster, did not attend his side's final home game of the season against Wigan due to his father's illness.
A statement released by Doncaster said: "Darren asks for privacy, and will provide an update through the club during the week."
Ferguson managed Manchester United for 27 years - making him the longest serving manager ever at the football club.
He is widely regarded as one of the best football managers ever, having won 38 trophies at Manchester United including 13 Premier League titles, five FA Cups, and two UEFA Champions League titles.
Ferguson was knighted in 1999 - the same year in which he guided Manchester United to a famous 'Treble' winning the Premier League, FA Cup and UEFA Champions League.
Ferguson recently made an appearance at Old Trafford on April 29 to present Arsene Wenger with a gift to mark his last season at Arsenal.
Messages of support have flooded in for the 76-year-old.
Sporting bodies such as FIFA, NBA, the Premier League and La Liga have sent their best wishes to the former Manchester United manager.
Foreign and domestic clubs have sent messages of goodwill, including local rivals Manchester City.
While several footballers have also tweeted their support.
Manchester United captain Michael Carrick said he was "devastated" by the announcement.
He wrote on Twitter: "All my thoughts and prayers are with him and his family. Be strong boss."