Tyson Fury has had his licence to fight temporarily revoked the day after he gave up his world heavyweight titles to focus on mental health problems.
The British Boxing Board of Control confirmed his licence was suspended "pending further investigation into anti-doping and medical issues".
Fury was charged with a doping offence by the UK's anti-doping body in June.
On Wednesday, Fury vacated his WBO and WBA world heavyweight titles, saying he was unable to defend them because of his health.
He will now have to meet with the BBBofC before a decision is taken on whether he can fight again.
He has an appeal hearing for his doping offence scheduled for November.
Earlier this month, Fury appeared to announce his retirement on Twitter, before backtracking several hours later.
He later revealed in an interview with Rolling Stone magazine that he was taking cocaine to help deal with depression.
Fury's uncle and trainer, Peter Fury, believes the former champion still has a future in the sport.
He told BBC Radio 5 live: "Once he produces all of his records of what he's been through, then I don't think the boxing board will have any option but to give him his licence back.
"This is a guy that's needed medical treatment. Once the powers that be say he's fit to box, then there's no reason why he can't be reinstated.
"He's at the pinnacle of his career. He's only 28. He's got a massive future."
Peter Fury also claimed that Fury would be "welcomed with open arms" by the boxing world once he does decide to return.
Meanwhile, promoter Eddie Hearn has said a deal is "very close" for British heavyweight champion Anthony Joshua to defend his IBF title against Klitschko, with the vacated WBA belt also on the line.
It is thought New Zealand's Joseph Parker and Mexico's Andy Ruiz Jr could now contest the WBO title.
Mick Hennessy, Fury's promoter, is confident that he will be back in the ring and says he remains "unbeatable" in the heavyweight division.
"The board of control need to help Tyson, not put any more problems his way," Hennessy told BBC Radio 5 live.
"They should realise what he has achieved and what he has been through. He doesn't need anyone firing any more arrows his way.
"Tyson wants to concentrate on getting himself better. He has been suffering with severe depression and that is being addressed. The signs are very good.
"If he gets himself together, he is an incredible fighter, an incredible athlete and he will be impossible to beat in the heavyweight division."
Mike Costello, BBC Radio 5 live boxing correspondent
"Fury needs to get himself medically fit. Then it's up to him, his uncle, Peter Fury, and promoter Mick Hennessy to decide what route they want to take.
"Will he be fit enough and able enough to go straight back in for a world title shot or will he need a warm-up contest before he fights again? It's so unclear at this stage because of the medical situation."
- 29 November 2015: Beats Wladimir Klitschko to become the WBA, IBF and WBO champion
- 8 December 2015: Stripped of his IBF title for failing to fight the mandatory challenger
- 24 June 2016: Postpones July's rematch with Klitschko after injuring an ankle in training
- 4 August 2016: UK's anti-doping body confirms it charged Fury with a doping offence on 24 June
- 23 September 2016: Postpones rematch for a second time because he is "medically unfit"
- 3 October: Appears to retire from boxing, tweeting: "I'm the greatest, and I'm also retired." Three hours later he reverses the decision, tweeting he is "here to stay"
- 5 October 2016: Reveals he has been taking cocaine to help him deal with depression
- 10 October 2016: Given extended deadline to convince the WBO not to strip him of his world heavyweight title
- 12 October: BBBofC meeting starts looking at Fury's boxing licence
- 12 October: Vacates WBA and WBO titles
- 13 October: Licence to box suspended by BBBofC