Manchester United captain Michael Carrick said he was “absolutely devastated”, adding: “Be strong Boss”.
The club’s Spanish goalkeeper, David De Gea, tweeted two prayer emojis for his former manager.
Absolutely devastated to hear about Sir Alex being unwell in hospital. All my thoughts and prayers are with him and his family. 🙏🏻🙏🏻🙏🏻🙏🏻 Be strong Boss xx
— Michael Carrick (@carras16) May 5, 2018
Those who played under Sir Alex, including David Beckham, Wayne Rooney and Peter Schmeichel, also posted to social media in support of their former boss, along with stars of the current team, such as Jesse Lingard and Romelu Lukaku.
Former Arsenal stars Thierry Henry and Robin Van Persie – who played under Sir Alex in his final season – wished him a speedy recovery, as did former footballer and pundit Gary Lineker.
Arsenal player Mesut Ozil posted to Twitter in support of Sir Alex, as did former Chelsea striker Didier Drogba.
A post shared by David Beckham (@davidbeckham) on May 5, 2018 at 1:15pm PDT
Thoughts and prayers are with Sir Alex Ferguson and his family! Stay strong 🙏🏿🙏🏿
— R.Lukaku Bolingoli9 (@RomeluLukaku9) May 5, 2018
Very sorry to hear the news that Sir Alex Ferguson is seriously ill in hospital. Wish him all the very best.
— Gary Lineker (@GaryLineker) May 5, 2018
Get well soon Sir Alex Ferguson. Hope he makes a full recovery 🙏🏼
— Mesut Özil (@MesutOzil1088) May 5, 2018
The Red Devils’ rivals Manchester City said they wished Sir Alex a quick recovery, adding the hashtag #footballfamily.
In a statement on Liverpool’s website, a spokesperson said Sir Alex was “a great rival but also a great friend”.
“The thoughts of everyone at Liverpool Football Club are with Sir Alex Ferguson and his family following the news that the former Manchester United manager is ill in hospital,” they said.
“A great rival but also a great friend who supported this club during its most difficult time, it is hoped that Sir Alex will make a full recovery.
“In the meantime, the club will offer its full support to Manchester United and also his family.”
Aberdeen, the club he managed before his managerial move to England, sent its “thoughts and prayers” as did Tottenham Hotspur.
Other clubs including Paris Saint-Germain, West Ham, Chelsea and Everton have also sent their wishes.
This evening, everybody at Chelsea FC sends our best wishes to Sir Alex Ferguson for a full and swift recovery following emergency surgery.
— Chelsea FC (@ChelseaFC) May 5, 2018
Olympic champion Sir Mo Farah, using the hashtag “legend”, said: “Get well soon Sir Alex Ferguson my support are with family and friends..!!”
Golfer Ian Poulter shared a photograph on his Twitter page of him sitting side-by-side with Sir Alex.
Television presenter Eamonn Holmes, a longtime friend of the football hero and Manchester United fan, described him as an “amazing man”.