Borussia Dortmund have reiterated that Mats Hummels is part of their long-term plans, despite ongoing speculation linking him with Manchester United.
Hummels said at the weekend that he is leaving his options open, having last week cast uncertainty over his Dortmund future.
The Germany international's current contract with the Bundesliga club expires in 2017, but CEO Hans-Joachim Watzke is optimistic about extending his stay.
"We continue to plan with him," Zorc said in kicker. "We will continue our dialogue with Mats regarding our collaboration."
Dortmund's 1-0 loss to Bayern Munich at the weekend leaves them 10th in the table, six points off the Europa League qualification places.
Kicker reported that the likelihood of a new Hummels contract could hinge on the direction, rather than the finances, of Dortmund, who take on Hoffenheim in the DFB Pokal quarterfinals on Tuesday -- their best chance of making the Europa League next season.
On Twitter, kicker reporter Thomas Hennecke added: "Mats Hummels is considering [his future]. And BVB offer him a new contract with a higher salary. It's prolong or say goodbye now."
With seven games left in the league, Dortmund trail seventh spot, currently held by Hoffenheim, by four points.
However, Jurgen Klopp's side have failed to score a goal in four of their last five competitive games, and following Tuesday's cup match travel to in-form Borussia Monchengladbach in the Bundesliga.