FC Tokyo could lose Yoshinori Muto this summer, but may have found their future in 13-year-old former Barcelona prodigy Takefusa Kubo, whose signing they announced on Thursday.

Kubo had been training with Tokyo's junior youth team since April. Hailed by Barcelona fans as the "Japanese Messi," Kubo signed with the Catalan giants in 2011 but lost his eligibility to play for them until he turns 18 after it was discovered the club had violated international transfer regulations by FIFA.

Arsenal and Manchester City were said to be among Europe's big clubs seeking to snatch Kubo but in the end, the teenager chose to return home.

"We hope in the future, he becomes a player who can carry the Japan national team or the Olympic team," Tokyo club president Naoki Ogane said of Kubo, who was recently selected for Japan's under-15s.

Muto's future, on the other hand, remained unannounced. The Japan striker would not say whether he had chosen Mainz or Chelsea as a summer transfer destination, and general manager Takayuki Tateishi dodged the press.

Muto also remains doubtful for this weekend's J. League showdown against Urawa Reds at Saitama Stadium after bruising his right knee during the national team's training camp on Tuesday.

Tokyo manager Massimo Ficcadenti said Muto's availability for the top-of-the-table clash could be a game-time decision.