Gary Mabbutt has confirmed Paul Gascoigne was taken to intensive care but said his condition is not life-threatening.
Gascoigne, who has long suffered with alcoholism, checked into a treatment centre in Arizona last week after his agent raised fears for his life.
Reports emerged that he had been taken into intensive care, and his former England team-mate Gary Lineker tweeted at 1am on Sunday morning: "Gazza is struggling, Let's hope he can hang on in there. Others have generously offered to help."
Mabbutt, who played alongside Gascoigne at Tottenham Hotspur, told Sky Sports News later on Sunday that the 45-year-old's life is not in immediate danger.
Mabbutt said: "Unfortunately over the last few weeks Paul has had a relapse, which culminated finally, last Monday, in Paul asking for help. By Monday afternoon he was on a plane out to Arizona to a clinic specialising in dealing with Paul's specific problems.
"The first thing he underwent was a detox - unfortunately Paul had a very bad reaction to the detox and the clinic decided that as a precaution it was best to transfer him to hospital.
"He was transferred to hospital in intensive care where they could monitor him 24-7, but I spoke to Paul's medical team in the UK this morning - they had spoken to Paul and he's recovering and hopefully soon he will be back into the clinic to continue his rehab.
"Over the years he has had a lot of support from the football family, but of course it could be a long road to recovery. Now Paul's asked for the help we can focus on getting through this.''
Dr John McKeown, a psychotherapist who has worked with Gascoigne for more than 10 years, later released a statement,
It read: "Following reports today I feel it's appropriate to bring people up to date on Paul Gascoigne's condition. Paul has experienced severe complications with his detoxification. This is not unusual for someone who has been drinking as heavily as he has.
"Paul was transferred from the US Clinic Cottonwood to a local hospital to be monitored so as to be completely satisfied that there are no other complications to his health.
"He is still receiving that care but the hospital has reassured me that he is up and about walking. There are no fears for his life. We will aim to keep everyone concerned updated on a regular basis."
Information from the Press Association was used in this report