Australian Open organisers have been handed a double blow as Venus Williams and Carlos Alcaraz have both pulled out of the tournament due to injury.
Former world number one Williams had been handed a wildcard into the Melbourne Grand Slam but sustained an injury in the ASB Classic in Auckland.
Williams reached the women's singles final of the Australian Open in 2003 and 2017 - losing to sister Serena Williams on both occasions - and she lost in straight sets to Alison van Uytvanck in the first round of the 2022 US Open.
Williams's wildcard place will instead to go Australia's Kim Birrell, whose best performance at the Grand Slam event was a third-round exit in the 2019 tournament.
Meanwhile, current men's world number one Alcaraz has also announced his withdrawal from the Australian Open owing to a leg injury sustained in his pre-season period.
The 19-year-old, who is the reigning US Open champion, was also due to take part in the Kooyong Classic next week before the start of the Australian Open, which begins on January 16.
However, Alcaraz confirmed on social media that he would be forced to pull out of the competition, saying: "When I was at my best in pre-season I picked up an injury through a chance, unnatural movement. This time it's the semimembranosus muscle in my right leg.
"I'd worked so hard to get to my best level for Australia but unfortunately I won't be able to play the Care A2+ Kooyong or the Australian Open. It's tough, but I have to be optimistic, recover and look forward. See you in 2024 @AustralianOpen ❤️."
The Spaniard was also forced to miss the ATP Finals and Davis Cup at the end of 2022 due to an abdominal issue, and he reached the third round of the 2022 Australian Open before losing to Matteo Berrettini.
Doubts are also persisting over the involvement of Emma Raducanu and Iga Swiatek, the former of whom rolled her ankle during her ASB Classic second-round match with Viktoria Kuzmova and retired in tears.
The French and US Open champion is now confirmed to have picked up a shoulder injury and will not compete at the Adelaide International 2 next week.