Gundogan's contract expires in the summer of 2016 and speculation is rife that United are on the brink of securing a €30 million deal for the Germany international, with the Gunners also waiting in the wings.
Sky Germany claimed on Friday night that United had effectively wrapped up a deal for the classy midfielder, who would sign an agreement with the Red Devils at the weekend, but although this report was slightly premature there's every chance the transfer will eventually happen.
"Gundogan's situation isn't straightforward because his contract expires in 2016," Zorc told Kicker, according to Goal. "There will be a decision soon."
Zorc also confessed that Borussia Dortmund are set to make several big changes this summer, but said the club are yet to receive a satisfactory offer for star defender Mats Hummels, another Manchester United and Arsenal target.
"As far as I know, Hummels's contract still runs until 2017. We did not receive any offer that we should think about," he added. "There will surely be some changes to the team this summer - maybe more changes than in recent years - but we won't radically change our team."
Big names set to leave Dortmund
With Borussia Dortmund out of contention to qualify for next season's Champions League campaign, and the club's influential manager Jurgen Klopp having recently announced his departure, several big-name players at Signal Iduna Park are expected to depart this summer.
Gundogan and Hummels currently lead the names of star players likely to leave the Bundesliga outfit, while the future of Marco Reus has also been plunged into uncertainty, even though the world-class winger only signed a new four-year deal in February.
That Gundogan's deal expires in just over a years time means there's every chance Borussia Dortmund will cash-in on the 24-year-old this summer.
Concerns over Gundogan
A fee of €30 million would be a huge sum of money for a player who recently missed 14 months with a back injury - and it seems Dortmund are keen to avoid losing Gundogan on a free transfer, as they did with Robert Lewandowski last summer.
Both Manchester United and Arsenal are on the lookout for a new top-class central midfielder and the fabulous Gundogan ticks all the boxes - provided he has now made a complete recovery from that problematic back injury.
Prior to his back injury - particular during the 2012-13 campaign - there were few better central midfielders in Europe.
And it increasingly looks as if his next destination will be the Premier League.
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