The 18-year old scored 13 goals last season for Kyoto Sanga, but may line up with countryman Shinji Kagawa should a rumoured summer transfer come to fruition
After scoring 13 goals in 33 matches last year for J-League Division 2's Kyoto Sanga, the 18-year-old striker was expected to be a pillar of his team's attack in his first year as a full professional.
But while the Kansai club are among the early favourites to earn promotion, they may lose their starlet to a top European club as early as August, when the summer transfer window begins.
Although several clubs across the continent have taken an interest in Kubo in the wake of his first call-up to Alberto Zaccheroni's Japan squad in February, Dortmund in particular has stood out as a team likely to acquire the youngster's services.
The current Bundesliga leaders are well-known for their discovery of Shinji Kagawa while he was just beginning to make waves with Japanese side Cerezo Osaka, and have a history of fostering young talent.
"While Kubo is under contract with Sanga, the club is prepared to make sure things go smoothly in the event of an overseas transfer," Nikkan quoted a source familiar with the player's situation as saying.
In Sanga's first win of the season against JEF Chiba United on Sunday, the youngster struck the crossbar twice and threatened on several more occasions.
"I wanted to score," Kubo told reporters after the match. "I feel like I would have contributed more to our win if I'd been able to convert those chances."