The Polish forward has continually been linked with a move away from the German champions, with Manchester United said to be keen on him.
However, Zorc has dismissed reports that Bayern have launched a €22m (£19m) bid to land the striker in the summer.
"If a player negotiates with another club, we cannot stop that," Zorc told Sport 11.
"But as we speak, we do not know anything about it. We do not comment on rumours, no matter what they are like."
Lewandowski has scored 18 times in all competitions this season.