Borussia Dortmund CEO Hans-Joachim Watzke has told Manchester United they "misjudged" their pursuit of Jadon Sancho.
The Dortmund chief insists there was a "clear line" on what it would take to prise Sancho from Westfalenstadion - but the Red Devils did not meet the requirements.
Sancho reportedly agreed to personal terms with United, but Dortmund's £109million price tag for the England international proved a stumbling block.
The Bundesliga club also set an August deadline for any bid for Sancho to be tabled, but United continued to pursue a cut-price deal for the 20-year-old right up to the transfer deadline.
Watzke believes the Red Devils were misguided in their strategy, but he refused to rule out a departure for Sancho in the future.
"[They] misjudged the situation. We would be more willing to compromise," he told ZDF Sports . "We had a clear line and will continue to do so next summer.
"In this industry, you can never say that a player is completely unsellable."
Watzke also reaffirmed his faith in Sancho's contract with Dortmund - which has three years remaining - when asked if he ever thought the player might leave.
He added: "I heard and read everywhere in the spring that Sancho was gone. But he's here. We had an agreement with him and it didn't look like that."
Should United pay Dortmund's asking price if they pursue Sancho next summer, or continue to bargain for a lower fee? Have your say here.
Meanwhile, Dortmund sporting director Michael Zorc explained earlier this month how the "door closed" on United's pursuit of Sancho.
He told Sky Germany : "We had clear agreements with him that he could make a transfer under certain circumstances, up to a certain point in time. And then the door closed."
Sancho has scored one goal and assisted twice in four appearances this season, while Dortmund are fourth in the Bundesliga.
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