Frank Bruno has been told he must earn the right to face Audley Harrison by proving he is a worthy challenger for the Olympic champion.
Former WBC heavyweight champion Bruno wants a £10 million comeback bout against Harrison at West Ham's Upton Park.
But Harrison's manager, Colin McMillan, believes the 41-year-old will need warm-up fights before facing his charge.
"It is definitely a fight that would generate an awful lot of interest," said McMillan.
"But first of all Bruno would have to have a couple of warm-up bouts to prove he is capable of fighting again at a high level.
"Bruno is talking about a one-off but I don't think he would be able to walk straight back into a fight against someone of Audley's calibre.
McMillan believes Bruno's health may be a stumbling block.
PA