Borussia Dortmund insist Neven Subotic is not for sale amid speculation that Manchester City were lining up a £20million January swoop for the highly-rated Serbian defender.

Subotic, 20, has been linked with a host of Premier League clubs over the past few months after earning rave reviews for his commanding performances at the heart of the defence for Jurgen Klopp's men.

Arsenal, Chelsea and Manchester United are understood to have been following his progress closely, while reports on Sunday claimed that City boss Mark Hughes was ready to table a big-money offer to lure him to Eastlands.

However, Dortmund general manager Hans-Joachim Watzke is adamant Subotic will not be leaving the Signal Iduna Park in the New Year even if City make a £20million offer.

"They could easily make us this offer if they would like to," said Watzke.

"But we are staying firm to our vow - Neven Subotic is not for sale."

Subotic, who only recently signed a new five-year contract, is flattered by City's reported interest, but is in no rush to leave the Bundesliga club.

He told German daily Bild: "It is a big honour if such a big club is attempting to sign me, but I am under contract until June 2014 at Borussia Dortmund and still want to achieve many things with this club."