"It hurts when I move my leg and it's pretty tough," Nakamura said after arriving at Narita airport, referring to a sprained right ankle he sustained in the Scottish Cup final against Dunfermline on Saturday.
Celtic defeated Dunfermline 1-0 in Saturday's Scottish Cup final to complete a league and cup double.
Nakamura earned both the Scottish Player of the Year and Scottish Football Writers' Player of the Year awards for his outstanding performance throughout the season.
Japan faces Montenegro in Shizuoka on Friday and then take on Colombia on June 5 in Saitama in its final warm-up for the defense of the Asian Cup in July.
Ivica Osim's team has been drawn against 2006 Asian Games gold medalists Qatar, the United Arab Emirates and Vietnam.
Putin's official spokesman Dmitry Peskov commented on remarks in the US media about failures in launching nuclear-capable missiles in Russia
More than 5.8 million people voted for Nicholas Maduro at the presidential election in Venezuela. This is more than a quarter of registered voters. Why did those people vote for the man, who, as Western media write, took Venezuela to the brink of collapse?
It has long been understood that the West has been trying to subject Russian borders to total control. We have not seen such activity even during the Cold War