Zorc dismisses Dortmund signings in January
Klopp's men have been hit hard with injuries to the likes of Marcel Schmelzer, Mats Hummels, Neven Subotic and Ilkay Gundogan during the first half of the Bundesliga season, seeing Dortmund slip to fourth at the halfway point.
After Dortmund won only one of their last six league matches going into the mid-season break, Zorc claims Klopp will rely on those returning from injury to help inspire a turnaround in fortunes.
"We will rely more on the players who come back from their injuries for the returning round," he told Bild.
"The good thing is that Gundogan and Schmelzer have fully trained before the Hertha game with the team. It is convenient for us that our injured guys can join the entire preparation."
Dortmund made a number of signings in the close-season to fill the void left following the departures of Mario Gotze and Felipe Santana, with Henrikh Mkhitaryan, Pierre-Emerick Aubameyang and Sokratis Papastathopoulos all moving to Signal Iduna Park.
Zorc believes the trio have fitted in well at Dortmund and expects them to improve in the second half of the campaign.
"They have done very well," he said.
"That fact that, after the many injuries, for them to be expected that they could already take leadership roles, would be a tall order. But they will be greater."