Naomi Osaka has effectively ended her season after pulling out of the Billie Jean King Cup.

The former world No. 1 has been sidelined since retiring from the China Open earlier this month.

She has since learned that her back injury was a lot more serious than thought after discovering a “bulged disc”.

Osaka has announced another withdrawal after pulling out of the Toray Pan Pacific Open in Tokyo over the weekend.

The four-time Grand Slam champion will not represent Japan at next month’s BJK Cup Finals in Malaga either, where they face Romania for a spot in the quarter-final.

Osaka has not played since she retired while facing Coco Gauff in the round of 16 in Beijing. She later revealed that she almost didn’t take to the court because her back locked up in practice. 

It was her last appearance of the year, as Osaka will now skip the BJK Cup Finals. “I've played so many tournaments this year, so it was definitely the toughest decision to not play this and obviously not play BJK,” she told reporters in Tokyo.

“I really honestly enjoyed it so much, and I think it helped with my development as a player.”

Opening up on the extent of her injuries, the world No. 56 added: “I thought I strained my back, but I did an MRI in Beijing, and they said that I bulged a disc in my back and I also raptured abdominal muscles.

“I was practising in Los Angeles in order to play here, but then I took another MRI and it said that I still have tears.”

It means Osaka’s comeback 2024 season is over. The Japanese tennis star returned from a 15-month break in January after giving birth to her first child last summer.

She has since climbed back inside the world’s top 60 after reaching quarter-finals in Doha and ‘s-Hertogenbosch. Osaka also made it to the last 16 in Rome and Beijing.

The two-time Australian Open champion recently linked up with a new coach, Patrick Mouratoglou. Their focus will now be on preparing for the 2025 season and the Aussie summer.