Dominic Thiem has pulled out of next month's Australian Open.
The 28-year-old Austrian, who was runner-up in 2020, has not played competitively since suffering a wrist injury in June, meaning he was unable to defend his US Open title.
Thiem suffered a setback in his recovery during a recent training camp in Dubai and, although he says he is fully fit again, the former world number three will skip Melbourne Park.
Thiem, now ranked 15 in the world, wrote on Twitter: "I am now feeling well again, my wrist is in optimal condition and I am practising normally with a very good intensity.
"After the short holidays, my team and I have assessed all matters and we have decided to make some changes to my initial tournament schedule.
"I will start the season in South America at the Cordoba Open in Argentina at the end of January, and will therefore not play this year at the Australian Open.
"I will miss the Australian fans, but I will be back in 2023. We believe this is the right decision in order to have a good return to competition."
Thiem was beaten by Novak Djokovic in five sets in the 2020 final, and there remains considerable doubt surrounding whether the three-time defending champion will compete for a 10th title in Melbourne.