Japan Under-23 defender Hiroki Sakai could be transferred from Kashiwa Reysol to Bundesliga club Borussia Dortmund this summer, German sports magazine Kicker reported Monday.

Sakai is contracted with Reysol through the end of the year, but Kicker said Dortmund has offered to pay a transfer fee of about €1 million ($1.3 million) to enable Sakai to join Dortmund, the team of Japan midfielder Shinji Kagawa.

The magazine also said fellow Bundesliga club FC Nuremberg have expressed interest in Japan midfielder Takashi Inui, currently with second-division Vfl Bochum.