Two-time champion Naomi Osaka has withdrawn from this year's Australian Open just eight days before the start of the tournament.

No reason was given for the 25-year-old Japanese player's withdrawal.

Organisers have promoted Ukraine's Dayana Yastremska to the main draw in her place.

A number of star names, including 42-year-old seven-time Grand Slam champion Venus Williams, and Spain's world number one Carlos Alcaraz, 19, have already withdrawn from the tournament which begins on 16 January in Melbourne.

It remains to be seen whether British number one Emma Raducanu will compete at the Australian Open after she rolled her ankle at the ASB Classic on Thursday and was forced to quit midway through a match.

Four-time Grand Slam champion Osaka retired from her second-round match as she defended the Pan Pacific Open in Tokyo in September.

She had been beaten in the first round of three tournaments including the US Open, prior to the Tokyo event. She also lost in the first round of the French Open in May and withdrew from Wimbledon in June because of an Achilles tendon injury, and reached the third round at last year's Australian Open.

In May 2021, Osaka pulled out of the French Open after revealing she had "suffered long bouts of depression" since winning her first Grand Slam title in 2018, and in September of that year she announced she would take a break from the sport.