The midfielder moved back to the Bundesliga in a loan switch this season having failed to make an impression at Spurs since arriving at White Hart Lane in 2007 from Hertha Berlin.
Having recently partially ruptured tendons in his knee, Boateng's campaign is to end prematurely with Zorc to assess his situation more closely at the season's close.
"It is sad this has happened now but we had already intended to discuss Kevin's future at our club at the end of the campaign," he told Bild.
When asked about Tottenham's valuation of the player he replied: "This is unrealistic!"
Injury blowBoateng admits his injury could not have come at a worse time as he bids to secure his future for next season.
"This is a real blow. I am out for a very long time and cannot shine for a while," he said.
"My goal is to remain a Dortmund player beyond the end of the season. This is my biggest dream.
"And now I am unable to impress the manager."