Real Madrid midfielder Takusa Fuso is facing a club v country row this summer.
Currently on-loan with Real Mallorca, the teenage Japan international is expected to do preseason with parent club Real Madrid.
However, Kubo is eager to be part of Japan's campaign for the Tokyo Olympics Games - which will also be held this summer.
It's been suggested Real coach Zinedine Zidane will want to take Kubo on their preseason tour to take a close look at the youngster - at the same time as the Tokyo Games are being held.
At Mallorca, Kubo has scored 3 goals and delivered 3 assists this season.