The Bundesliga champions are willing to listen to offers for the highly-rated attacker after he intimated that he will not extend his contract, which expires next summer
The Japan international's future at Signal Iduna Park has been a hot topic in recent weeks, given that he is about to enter the final year of his contract with the club.
"I had a meeting on Monday morning with his agent - Shinji Kagawa told him that he definitely will not extend his contract with us," Zorc is quoted as saying by Revier Sport.
"Should offers come now for Kagawa, we will deal with them and negotiate."
Manchester United have been tipped as front-runners in the race for Kagawa's signature, with manager Sir Alex Ferguson present to watch the 23-year-old grab the opening goal in Dortmund's 5-2 DFB-Pokal final victory over Bayern Munich on Saturday.
It is widely reported that the Bundesliga champions will listen to offers in the region of €15 million for the former Cerezo Osaka attacker, who moved to Dortmund in 2010 for €350,000.