Japan's "Ice Prince" Yuzuru Hanyu skipped training Monday ahead of this week's world figure skating championships, triggering fresh fitness fears over the Olympic champion.
The 24-year-old, who retained his Olympic title last year after an injury-hit build-up, opted against an early morning practice in Saitama as he continues to recover from strained ankle ligaments that sidelined him for December's Japanese nationals.
Hanyu's coach Brian Orser insisted he was "very confident" the two-time world champion would be fit, guaranteeing a fresh wave of "Yuzu-Mania" from the skater's legions of adoring female fans who shower him with stuffed Winnie the Pooh bears after his performances.
But with Hanyu struggling, American Nathan Chen arguably starts as a slight favourite to defend his world title, despite having to balance his studies at Yale university.
"I'm really glad I gave myself a shot to attempt both," said the 19-year-old, who landed a record six quad jumps in a programme at the 2018 Pyeongchang Games in winning the free skate, though still finished outside the medals.
"My skating has been going well too, so I can't complain. The worlds is a whole other ballgame."
Hanyu's arrival in South Korea last year was also shrouded in mystery after he twisted his ankle just weeks before the Olympics.
The snake-hipped superstar has been training in secrecy once more in the run-up to the world championships in Saitama, where he captured his first world title in 2014 a month after winning gold at the Sochi Olympics.
Hanyu needed painkilling shots in Pyeongchang, where he became the first man to capture back-to-back Olympic figure skating gold medals in 66 years.
- PM's crushed tangerine -
His gutsy performance broke the internet, while Japanese Prime Minister Shinzo Abe admitted he had got so excited watching on television he almost squashed a tangerine to a pulp.
Meanwhile, fellow Japanese Shoma Uno, who took silver behind Hanyu at the 2018 Olympics, also skipped practice on Monday -- to the disappointment of more than 200 waiting press.
Few would bet against Hanyu should he recover, but Chen and Uno -- who swept to gold at the recent Four Continents meet with a record-breaking free skate -- will push him close.
The host nation will be hoping teenage sensation Rika Kihira can replicate her form during a remarkable senior debut season as she seeks to become the first Japanese women's world champion since Mao Asada in 2014.
Kihira stormed to victory in both her grand prix events, the Grand Prix Final and the Four Continents, and the 16-year-old promised to put on a show for the home fans.
Olympic champion Alina Zagitova will be her biggest threat as the Russian tries to atone for a fifth-place finish at last year's worlds.
"It's my first world championships and there will be a few nerves skating at this big Saitama rink," Kihira told reporters.
"But I'm happy to be able to skate in Japan and will look to execute two solid skates with no mistakes."
France will look to plunder gold in the pairs through Vanessa James and Morgan Cipres, with Gabriella Papadakis and Guillaume Cizeron favourites in the ice dance.