Australian Open organisers are still unsure if defending men's champion Novak Djokovic will play at next month's Grand Slam.
Serbia's Djokovic, 34, has not spoken publicly about his vaccination status.
All players and staff at the Australian Open must be vaccinated or have a medical exemption granted by an independent panel of experts.
"If Novak shows up, he'll be vaccinated or have a medical exemption," said tournament director Craig Tiley.
However, Tiley is confident Spain's Rafael Nadal will be there despite testing positive for Covid-19 this week.
The Australian Open starts in Melbourne on 17 January, with players starting to arrive in the country over the next week for warm-up events.