Ilkay Gundogan
Ilkay Gundogan's future uncertain after Dortmund admit they will sell. Getty

Borussia Dortmund insist they are still to receive an offer for Manchester United target Ilkay Gundogan.

The Bundesliga giants on 8 May confirmed Gundogan, 24, will be sold this summer after the midfielder refused the club's offer of a contract renewal, with his current deal set to expire next summer.

United were widely reported to have made an approach for the Germany international in April while Arsenal and Bayern Munich also remain linked with the player.

But while Dortmund have made it unequivocally clear Gundogan will move on in the coming months, the club's sporting director Michael Zorc insists that revelation is yet to invite any bids.

"We have already finished talking with the player and as he did not want to extend his relationship with us, we have thought that he could leave this summer, although it will depend on the offers that reach the club," Zorc said, Sky Sports report. "At the moment, none have arrived."

In April, a number of reports in Germany suggested United have struck a deal worth £21.5m to bring Gundogan to Old Trafford.

United's need to strengthen their midfield options have been greatly exposed in recent weeks during the absence of Michael Carrick, who will miss the remainder of the season with an ongoing calf problem.

United again struggled without the veteran midfielder as they laboured to a 2-1 win over Crystal Palace on 9 May and prior to that game, manager Louis van Gaal made it clear finding a long-term replacement for Carrick will be a priority this summer.

He said: "It is clear that Carrick is very important but that is also because we have only one right-sided holding midfielder. That is what I am saying already in the whole of the season, that our selection is not balanced, and I want to restore that in the next transfer period.

"Life is not ending at 34, but for a professional football player, it is close by. That is why I have to handle again in that position."

Van Gaal has already shown he is prepared to move forward with transfer business before the end of the season if he feels it is in the best interests of the club. Earlier in May, United confirmed Memphis Depay will join the club in June, a move prompted when the Netherlands international entered talks with Paris Saint-Germain over a move to France.