The left-footed deadball specialist said he feared missing a warm-up friendly at home against Montenegro on Friday and, in the worst case, another against Colombia on June 5.

Nakamura was one of the three Europe-based players who were called up by Japan coach Ivica Osim on Sunday for the friendlies.

The others were Eintracht Frankfurt striker Naohiro Takahara and Basel's defensive midfielder Koji Nakata.

"It hurts when I swing my leg and it's pretty tough," Nakamura told Kyodo News as he arrived at Tokyo's Narita airport Monday.

The 28-year-old was injured in Celtic's 1-0 win over Dunfermline in the Scottish Cup final on Saturday.

He twisted his right ankle when he tried to avoid a sliding tackle in the 70th minute. He kept on playing until Gordon Strachan's team lifted their Cup through Jean-Joel Perrier Doumbe's 84th-minute goal.

Nakamura was due to undergo medical check-ups after returning here.

"It will be no good if I force myself to play and suffer from the consequences," Nakamura, who has been voted both the Scottish Player of the Year and Scottish Football Writers' Player of the Year, told Japanese reporters in Glasgow before leaving for home.

He also admitted he would need a lot of time to train together with J-League players who have dominated Osim's national team since he took over from Brazilian legend Zico after Japan's winless exit from the World Cup finals last year.

"It is not yet clear who will play what. You can't match a strong side unless you can play with your eyes closed," he said.

Osim, the gruff Bosnian strategist, did not use overseas-based players in his first seven matches as Japan coach. He called up Nakamura and Takahara in Japan's last international match in which they beat Peru 2-0 at home in March.

"I played briefly last time. But it is going to last long this time," Nakamura said in Narita. "I want to absorb the style of football by this national side."

The 27-strong squad for the upcoming friendlies did not include Galatasaray midfielder Junichi Inamoto who was reportedly looking for a new club in Europe and also considering undergoing surgery to remove screws from his left leg during the close season.

But he was seen likely to be called up for the Asian Cup finals in which Japan are booked in the same group as 2006 Asian Games gold medalists Qatar, the United Arab Emirates and Vietnam.

Osim said in a statement, "I have selected players who have played well for a relatively long period of time, not those players who have gone up and down in J-League matches."