Sochi Olympic champion Yuzuru Hanyu has sustained ligament damage to his right foot and may be sidelined longer than expected, Japan Skating Federation director Yoshiko Kobayashi said Wednesday.

Should the two-time world champion continue to take time off skating and delay his preparations for the upcoming national championships, he could miss the Dec. 21-24 competition in Tokyo that also doubles as a qualifier for the Pyeongchang Winter Games.

"It became apparent that I injured my ligament, which normally takes longer to heal than a sprain," according to a statement from Hanyu read out by Kobayashi.

"The plan is to take the ice and start with basic moves like strokes and crossovers mainly on my left foot, then gradually work my way up to turns using my right foot," the statement said.

Hanyu, who is currently back at his training base in Toronto, had said through the JSA on Nov. 12 that he had been told by his doctor he would need 10 days of complete rest and guessed he would regain fitness in three to four weeks.

Even if Hanyu misses the national championships, he is practically assured of an Olympic berth based on his No. 1 world ranking and other criteria. At this point he has expressed his desire to compete, according to Kobayashi.

Hanyu sustained the injury to his ankle and knee while attempting a quad lutz during practice at the NHK Trophy on Nov. 9.

The 23-year-old became the first Japanese to strike Olympic gold in men's figure skating in 2014, and is looking to become the first man in 66 years to capture back-to-back Olympic titles. American Dick Button did it last at the 1948 and 1952 Games.