Ole Gunnar Solskjaer has not given up hope of signing Sancho, despite Dortmund insisting privately they will keep the 20-year-old for at least another season.
Despite making progress with wages and agent fees, United are adamant they will not pay the €120 million asking price and are ready to pursue other targets to fill the hole in the squad.
With just three weeks before the transfer deadline, the possibility of negotiating a loan deal for an experienced alternatives like Douglas Costa, Kingsley Coman, Ivan Perisic or Gareth Bale is being explored.
Sources have told ESPN that even if a deal cannot be reached this summer, Sancho is likely to remain a target in 12 months' time.
The financial impact of the coronavirus pandemic has allowed United to become clear frontrunners for Sancho this summer but there is an acceptance that may not be the case next year, and that the former Manchester City youngster would have more options to continue his career away from Dortmund.
Meanwhile, sources have told ESPN that United are continuing to monitor Sergio Reguilon's situation at Madrid.
United have been offered the chance to sign the Spain left-back, who spent last season on loan at Sevilla, and although conversations have taken place between chief negotiator Matt Judge and the 23-year-old's representatives, an official bid has not been lodged.
Tottenham are also interested in Reguilon, although he has not ruled out staying at the Bernabeu to fight for his place.