The 25-year-old, who joined from Stuttgart in 2012, is yet to truly establish himself at the Westfaledstadion and West Ham, Wigan and Celtic have been among those linked with a move.
Fellow Bundesliga outfit 1899 Hoffenheim have also been reported to be tracking the former Germany Under-21 international, who failed to score in his 12 league appearances last season.
Schieber has another two years remaining on his current contract with Dortmund, but Zorc says that they would be prepared to sell if the striker is looking to leave.
"We have been talking to Julian Schieber and his agent in the last week," he told kicker-Sportmagazin.
"He had been out to have his Borussia Dortmund breakthrough within his first two years at the club.
"If he is out for a transfer after these first two years at our club, we would certainly be considering that. Of course."
Meanwhile, Zorc has confirmed some transfer business for Dortmund as 20-year-old striker Marvin Ducksch has joined newly-promoted Paderborn on a season-long loan.
Zorc said: "We have agreed a loan deal with SC Paderborn to ensure Marvin Ducksch has the chance of regular first-team practice in the Bundesliga.
"This is going to help him in his development as a player."