Former Celtic star Shunsuke Nakamura is facing a battle to be fit for Japan's World Cup warm-up match against England, reports said on Saturday.

The 31-year-old midfielder, who has been struggling with a left ankle problem, was below par in Japan's recent 2-0 home defeat at the hands of arch-rivals South Korea and was substituted in the second half.

He played only the first half of a practice game in Japan's training camp in Saas-Fee, Switzerland, on Friday.

Japan coach Takeshi Okada said Nakamura needed more time to recover full fitness and he was unsure whether he would play in Sunday's friendly in Graz, Austria.

"He (Nakamura) is not in his best form, his fitness is not perfect," Okada was quoted as saying by the daily Sports Nippon.

But the veteran player said he was improving. "With my ankle getting better, my fitness will get better," he told the Tokyo Shimbun.

Japan play Cameroon in their opening Group E fixture in the World Cup on June 14, followed by games against the Netherlands and Denmark.

"It's special to play in the World Cup. It will be a difficult competition. I want to do my best," said Nakamura, who failed to impress at Espanyol after leaving Celtic, returning to his old club Yokohama Marinos.

Okada, who has often faced criticism for relying too heavily on stars Nakamura and Yasuhito Endo, said after losing to South Korea that he may use a defensive system.

During their training camp, Okada tested a defensive formation with CSKA Moscow midfielder Keisuke Honda as a lone striker.

Okada, who took Japan to a winless World Cup finals debut at France 1998 in his first stint as national coach, came under fire for offering his resignation in the wake of the South Korea defeat, which followed a 3-0 loss to Serbia.

Japan play their last warm-up game against Ivory Coast on June 4.

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