Celtic legend in an intensive care unit, hospital chiefs confirmed this morning.
The ex-defender's condition has been described as stable following surgery after he after taking his dog for a walk.
The 46-year-old former Hoops and Scotland star suffered a 'bleed on the brain' according to old team-mate John Hartson.
Doctors at Hull Royal Infirmary issued a statement today, the Daily Record reports.
It said: "We can confirm Jackie McNamara was admitted to Hull Royal Infirmary on Sunday night and is currently being cared for in our Intensive Care Unit. He remains in a critical but stable condition.
"We are supporting both Jackie and his family, who request their privacy to be respected at this time."
It comes just hours after Jackie's daughter posted on Twitter thanking well-wishers for their support.
The tweet read: "Thank you for all your kind words and support.
"My dad is getting the best care possible, as you can all understand this is difficult for us as a family and request privacy at this time."
According to a pal Jackie was walking his dog near his home in York before taking ill.
He said: "He became unwell quite quickly and he headed back to his house.
"But he must have been really poorly because he did not make it back into the house.
"He collapsed on the doorstep and his family found him. So this is a really worrying time for his family and his friends.
"We're just hoping that he can come through this."
McNamara, who won 33 caps for Scotland and made 256 appearances, remains in intensive care.
A number of McNamara's old team-mates at Celtic and Aberdeen have issued their support for the 46-year-old as they wait on news.
McNamara was manager of York City FC until March 2018.
He is now a consultant with Dunfermline Athletic where his football career began in the early 1990s, though he still has a house in north of England.
