Olympic champion Yuzuru Hanyu said on Sunday he needed 10 days of "complete rest" after damaging ankle ligaments and hopes to be back skating competitively in four weeks.
The injury, sustained on the eve of the NHK Trophy, is a big setback with just three months to go until he is due to defend his gold medal at Winter Olympics in Pyeongchang, South Korea.
"I was told by my doctors that I am to have complete rest for 10 days. I hope to fully recover in three to four weeks, but this is tentative," Hanyu said in a statement.
"I will work hard on my treatment and rehabilitation to be in time for the nationals (in December)."
The reigning world champion fell and twisted his right ankle while attempting the ultra-tough quadruple Lutz during practice Thursday at Osaka's Municipal Central Gymnasium.
He was able to skate off the ice and walk unassisted, but was limping. Shortly afterwards, he returned to the ice and resumed practice but on Friday he withdrew from the NHK Trophy, which he had won for the past two years.
He told national broadcaster NHK, a co-organiser of the event, that he was focusing on the Olympics.
The national championships serve as the final trial to decide which skaters go to the Olympics.
"Truly, there is only little time left before the Pyeongchang Olympics. All I can do is to do whatever needs to be done in front of me and take one thing at a time," he told NHK.
"I wish to return to the ice by completely healing the injury."
In Hanyu's absence, Russian Sergei Voronov grabbed his first Grand Prix victory Saturday. His compatriot and teenage two-time world champion Evgenia Medvedeva won the women's event.
In the pairs, Chinese Sui Wenjing and Hang Cong finished first also on Saturday.
Canadian team Tessa Virtue and Scott Moir triumphed in the ice dance to round off competition on Sunday.
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