Two British and Irish Lions players are isolating after one of the management team tested positive for coronavirus.
Organisers say Wednesday's game against the Sharks will go ahead provided another round of testing does not produce any more positive results, but kick-off will be moved to 19:00 BST.
Saturday's game against the Bulls was postponed because of Covid-19 cases in the hosts' camp, while South Africa's match against Georgia was cancelled.
The Lions' first Test is on 24 July.
Two members of staff are also isolating at the team hotel and a Lions statement said all members of the touring party "have since been tested", adding that further updates would "follow in due course".
"We have followed all necessary precautions since the start of the Tour, which included regular testing and rigorous Covid-19 counter measure planning and protocols," said Lions managing director Ben Calveley.
"Our priority is to ensure the health and safety of the entire touring party, which is why we quickly isolated the players and staff upon receiving the news of the positive result.
"Everyone has subsequently been lateral flow and PCR tested. The Medical Advisory Group await the results of the PCR testing in order to make a decision on tonight's game."
After months of uncertainty, organisers opted to go ahead with a South Africa tour rather than pursue contingency plans to play at home or in Australia.
The side - who have been playing and training in a strict coronavirus bubble - arrived as South Africa was battling a third wave of infections, with the Springboks having to isolate twice in the past two weeks.
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