Borussia Dortmund have reacted cautiously to speculation that forward Youssoufa Moukoko, the youngest player and scorer in Bundesliga history, could be leaving before the end of the transfer window. The 19-year-old has been subject of transfer speculation because he is not getting much playing time, and he was not part of coach Nuri Sahin’s squad for Saturday’s 4-1 German Cup win against Phönix Lübeck. “The transfer window is still open for a few days. Of course we will hold more talks. Right now there are no decisions. We are waiting to see what is yet to come,” sporting director Sebastian Ke…