Bolton Wanderers' Fabrice Muamba was in a stable but critical condition on Monday, two days after he suddenly collapsed during a match, the hospital treating him said.
Muamba slumped onto the turf towards the end of the first half of an FA Cup quarter-final at Tottenham's White Hart Lane ground on Saturday.
It was later confirmed the 23-year-old had suffered a cardiac arrest.
A statement issued on behalf of Bolton and the London Chest Hospital at 9.30am local time (0930GMT) Monday said: "Fabrice Muamba's heart condition is stable, but he remains critically ill in intensive care at The London Chest Hospital.
"The family is grateful to the media for continuing to respect their privacy at this time."
Muamba's plight sparked a wave of concern from fellow Premier League players and football fans worldwide.