Birmingham City Football Club's chief executive Karren Brady is awaiting surgery for an aneurysm in her brain.
The 36-year-old was expected to have a lengthy operation at a London hospital to stem the flow of blood through the weakened blood vessel, which had caused it to "balloon".
If the aneurysm bursts it will cause a potentially fatal haemorrhage, but doctors diagnosed her condition last week before it had chance to rupture.
Ms Brady is now expected to undergo a less invasive procedure later this week.
In a statement she said: "I am really touched by all the goodwill and get well messages the club has received on my behalf, and I would like to thank the fans for their continued support."
David Gold, co-owner, said: "We discovered the doctors wanted tests, with a view to a less invasive treatment."