Former world number one, Andy Murray was screened positive for covid-19.
The 33-year-old Brit was training for the first Grand Slam of the year, the Australian Open.
He was due to fly to Australia on one of the 18 charter flights planned by the tournament organizers, but is now isolated at home.
Murray, who is said to be in good health, expects to be able to arrive in Australia at a later date and yet play in the tournament that starts on 8 February.
Murray, the three-time Grand Slam champion, is a five-time finalist at the Melbourne event.