The 29-year-old Tokashiki is now expected to miss out on Tokyo 2020 after suffering the injury during a match with domestic team Eneos Sunflowers. 

Her side had beaten Fujitsu Red Wave 78-59 in the quarter-finals of the All-Japan Championship at Yoyogi National Gymnasium.

Tokashiki has previously played for Seattle Storm in the Women's National Basketball Association in the United States and is a seven-time Women’s Japan Basketball League Most Valuable Player (MVP). 

She has also been a key player for Japan and has been named MVP at two International Basketball Federation (FIBA) Women's Asia Cups.

"I’m full of disappointment after finding out the extent of my injury, but I would like to do my best so I won’t waste a single day with the goal of getting back to the game that I love," Tokashiki said. 

Japan had already lost another star player, Nako Motohashi, after she also tore her ACL at a training camp in November. 

Tokyo 2020 will be the eighth Olympic appearance for the Japanese women's basketball team.

Their best finish has been fifth at Montreal 1976, with the squad placing eight at Rio 2016. 

Tokashiki has won three FIBA Asia Cups with Japan, including one in 2019.

The next edition of the Olympics in the Japanese capital is scheduled for July 23 to August 8 after it was postponed due to the COVID-19 pandemic.