The Norway international has been prolific since joining the Bundesliga club midway through the 2019-20 season, scoring 43 goals in as many appearances in all competitions.
Haaland's contract is rumored to include an agreement allowing him to leave for a €75million fee at the end of the 2021-22 campaign.
Raiola, the striker's agent, said this week that a list of potential buyers only just reaches double figures, with four possible destinations in the Premier League.
While Dortmund sporting director Zorc has no problem with Raiola speaking out on Haaland's future, he believes even fewer clubs would appeal to the 20-year-old if he decides to move on.
"It is clear that Erling Haaland can't and won't pick just any club after his time at Dortmund," he told a media conference.
"I can't even pick out 10 possible clubs. So, there is no dissent. It was a normal statement he [Raiola] has to give from time to time.
"We are happy to have Erling here with us and that he has scored in the last games and proven his value for us. I can only say that we will continue to plan with him and I don't think he is uncomfortable here in Dortmund."
The Spanish side acquired him in a deal worth a reported €7.5m in 2019, but Dortmund managed to retain a buy-back clause.
Zorc did not reveal if Dortmund were interested in re-signing Isak, but confirmed the club are keeping a close eye on the Sweden international's progress.
"We think he made the right step going to Real Sociedad," he added. "In the beginning, he impressed as a substitute and scored goals.
"He has become a regular starter this season and scored a lot of goals in the past weeks. Of course, we are following all that."