DORTMUND, Germany (AP) Borussia Dortmund captain and central defender Mats Hummels has asked to be released from his contract so that he can move to Bundesliga rival Bayern Munich next season.
Dortmund said on Thursday it was willing to let Hummels go for ''an extremely valuable offer that would reflect the player's extraordinary worth.''
The club added that Bayern had not made an offer yet. Hummels still has one year on his contract and no opt-out clause.
Hummels was on the Germany squad that won the 2014 World Cup in Brazil - scoring the winner against France in the quarterfinals - and is a key player for Dortmund, which is second in the Bundesliga behind Bayern.
He would be the third Dortmund star to leave for Bayern in recent seasons, after striker Robert Lewandowski and attacking midfielder Mario Goetze - scorer of Germany's winning goal against Argentina in the World Cup final two years ago.
The 27-year-old Hummels started his career with Bayern, playing mainly for the reserves, before joining Dortmund permanently in the 2009-10 season, following a loan spell.
Hummels' parents and other family live in Munich, his hometown.
He recently spoke publicly about contemplating a move to another club, without naming Bayern, saying it was a difficult decision that was making him lose sleep.
German media have speculated that Goetze could return to Dortmund because he has been rarely used by coach Pep Guardiola. Guardiola is leaving at the end of the season for Manchester City, to be replaced by Carlo Ancelotti.