World number one Novak Djokovic has withdrawn from Serbia’s ATP Cup team.
There remains uncertainty over whether the 34-year-old will compete at the Australian Open, which begins in Melbourne on 17 January.
All players and staff at the 2022 Australian Open must be vaccinated or have a medical exemption granted by an independent panel of experts.
However defending champion Djokovic has not spoken publicly about his vaccination status.
The nine-time Australian Open winner has been replaced by world number 33 Dusan Lajovic for Serbia in the 16-country ATP Cup, which begins in Sydney on Saturday.