The British and Irish Lions' tour of South Africa could fall victim to the coronavirus pandemic if travelling fans are prevented from attending.
That is the warning from South Africa Rugby chief executive Jurie Roux, ahead of next year's tour which is scheduled to start with a first Test on July 24.
Roux told a press conference: "There has been some talk of moving it out [to a new date], but our travel advice is that by June/July, we should be at what is deemed to be normal international travel.
"But we are monitoring it on a monthly basis. Travelling for international events will likely still be under more pressure than pre-Covid [in July 2021].
"No spectators and people not being able to travel would not make this commercially viable and then we would discuss how we continue with the tour."
The Lions will be led in South Africa by former Wales and current Gallagher Chiefs head coach Warren Gatland, who guided them to victory in Australia in 2013 and a draw in his native New Zealand four years later.
A five-week tour programme is due to get under way in Cape Town on Saturday, July 3 when the DHL Stormers provide the opposition in the first of five matches before the first Test at the FNB Stadium in Johannesburg.
They will return to Cape Town a week later for the second Test and complete the series at Johannesburg's Emirates Airline Park on Saturday, August 7.