The 22-year-old Serbian international has been strongly linked with a £20million move to Chelsea.
“We will not sell any player this winter, full stop,” Watzke told Nachrichten.
“We do not even think about selling anyone during the summer. Should there be a fantastic offer dropping in for any player and given this offer would be also of significance for Borussia Dortmund, we would still remain very much unprepared to sell.
“Of course, in a given case we would consider it. Anyway, we are not allowing any young player to leave us.”
