The German club have publicly stated that they will listen to offers for the England winger.
With two years remaining on his contract, Dortmund have decided to lower their original asking price.
Eurosport claims United are confident of landing Sancho as he will now cost £85m, down from the £108m previously sought by Dortmund.
The Red Devils are likely to open the bidding at £65m-£75m.
However, Ole Gunnar Solskjaer could have a battle on his hands in his pursuit of Sancho.