Borussia Dortmund are no ready to sell Serbian defender Neven Subotic, responding to reported interest from Manchester City. Reports on Sunday claimed that City have tabled a £20million bid for the highly-rated 20-year-old. "They could easily make us this offer if they would like to," Dortmund general manager Hans-Joachim Watzke said on Monday. "But we are staying firm to our vow - Neven Subotic is not for sale."