Four-time Grand Slam champion Naomi Osaka on Monday pulled out of her home Japan Open next week because of an injury that caused her to retire from the China Open in Beijing.
"Due to injury, Naomi Osaka will not participate" in the WTA 250 tournament in the city of Osaka from October 14-20, the Japan Tennis Association said in a statement.
The 26-year-old former world No 1 looked in good touch as she recorded three wins at the China Open in Beijing last week.
But in her last-16 match, against eventual champion Coco Gauff, Osaka retired at the end of the second set because of a back injury.
"So I locked my back up during practice earlier and honestly wasn't sure if I could even play but I just wanted to try," she said on social media.
"Unfortunately things just got progressively worse during the match."
Osaka's last WTA tournament appearance in her home country was a fleeting one, two years ago at the Pan Pacific Open in Tokyo.
She won a first-round match after one game when opponent Daria Saville retired.
Osaka then withdrew with abdominal pains before her second-round match.
It was her last tournament before taking leave to give birth to her daughter Shai in July 2023.
Osaka returned to the tour in January this year but has struggled to recapture the form that saw her win two Australian and two US Opens between 2018 and 2021.