Aubameyang, 27, admitted on Tuesday in an interview with RMC that he is weighing up his future, telling the French radio station that, although he feels "very good" at Dortmund, he is not sure he will stay at the club beyond the summer.

The Gabon international has been outspoken about his future in recent months and, despite being under contract until 2020, it looks likely he will depart the club in the next transfer window with Real Madrid, Manchester City and Paris Saint-Germain all linked.

Although Dortmund have said they are open to discussing a transfer should a club make the right offer, they are now running out of patience with the attacker amid a turbulent period at the Westfalenstadion.

"I recommend to him to give less interviews about the summer," Zorc told Reviersport. "We chatted briefly, and I recommended to him to give less interviews about the summer and rather focus on our chase of a Champions League spot on the pitch.

"He understood it. We have a very, very good relationship, but we needed to set an example for the inside and the public that our focus now is on the sporting side."

On Saturday, Dortmund host RB Leipzig. The newly-promoted side beat them 1-0 in the reverse fixture, and they have opened an 11-point gap on Dortmund -- in fourth place -- after only 18 matches.

Dortmund have drawn four of their last five league games but, despite only suffering one defeat from their last 17 competitive matches, coach Thomas Tuchel has come under fire from the media, and also the club's fans.

"[The unrest] is bigger than two years ago when we were bottom of the league under Jurgen Klopp," Zorc told German football magazine kicker.