Naomi Osaka out of Australian Open, replaced by Dayana Yastremska

Naomi Osaka has decided not to play at the Australian Open.

The organizers of the Australian Open said on Sunday that Osaka won't be playing in the tournament.

She hasn't played since September after withdrawing during the second round of the Tokyo tournament. At that tournament, she won her first-round match when Australia's Saville withdrew with a knee injury.

Osaka lost in the first round of her previous tournaments, including the US Open, where she is a two-time champion.

She had been considered unlikely to play in the first Grand Slam of the season after posting pictures on social media of a trip to Europe with her boyfriend.

The main draw has been changed to accommodate Dayana.

After missing the French Open, Osaka took a mental health break and later said she had been struggling with depression and anxiety for a long time. There is uncertainty over when or if she will return to work.

Carlos Alcaraz, the world's top ranked man, withdrew from the Australian Open on Saturday with an ankle injury.

Simona Halep, a former finalist, is not playing this year, as well as Venus Williams, who has given back a wild-card entry due to injury.