The 2016 Olympic women's badminton gold medallist, Spaniard Carolina Marin, said on Tuesday that she would not be able to defend her title in Tokyo next month due to an injury.
The 27-year-old said she had torn the meniscus and anterior cruciate ligaments in her left knee, which would require surgery.
Carolina, who has also won the World Championships three times and is currently ranked fourth in the world, suffered the injury in training on Friday, reports Xinhua.
"After tests carried out over the weekend and consultation with the doctors, it has been confirmed that I have a torn anterior cruciate ligament and both menisci in my left knee. I will have to have surgery this week and start my recovery," Carolina posted on her social media sites.
Carolina was one of Spain's best hopes for a medal in Tokyo after starting the year with two Super 1000 wins in Thailand, along with triumphs in the Super 300 in Switzerland and the European Championships in Kiev.
"I want to thank everyone for the support and messages in the past few days. This is another setback for me, but I have no doubts that I will return," said Carolina.
"Despite the fact that the preparation in the last two months had become very difficult, I was very excited about going to the Olympic Games in the best possible shape, but unfortunately that can't be," said the Spaniard, who won the gold in Olympics 2016 final defeating India's PV Sindhu.