The in-demand striker revealed he felt he was under pressure from Dortmund to make a decision about his future.
Haaland, 22, has two years remaining on his contract but a £66m release clause will become active this summer.
"Erling's statements surprised us a bit," Zorc told Kicker.
"There is currently no deadline, no deadlines, and there have not even been any discussions.
"But that we want and have to have talks at some point is clear, understandable and only professional."
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