Manchester United have made just one signing this summer, bringing in Donny van de Beek from Ajax, but fans have been desperate for more additions before the window slams shut.
The Red Devils are working on a number of potential incomings and outgoings before next week's deadline in a bid to strengthen the squad.
The potential move would see United fork out an initial £75m, with a further £15m to be paid in add-ons.
However, Dortmund have been holding out for their asking price of £108m and it remains to be seen whether the parties can strike a deal with so little time remaining in the window
Left-back Alex Telles has also been heavily linked with United but, again, the Red Devils are unwilling to pay Porto's asking price given the Brazilian's contract is due to expire next season and he will be available to negotiate a pre-contract agreement with any club in January.
Ole Gunnar Solskjaer has been desperate to get rid of players this summer but the only major outgoing has been Alexis Sanchez joining Inter Milan on a free.
Transfers away from Old Trafford for defenders Chris Smalling and Marcos Rojo are being worked on, with the Manchester Evening News reporting that they are both training away from the first team in a separate bubble in the hope of securing moves.
Roma's interest in bringing Smalling back to the Stadio Olimpico on a permanent basis is no secret and reports from Italy claim the Serie A side a readying a new bid, with the player pushing for the move.
Rojo's agent Jonathan Barnett has admitted that an exit is "more than likely", with Lazio mooted as a potential destination.
Midfielder Andreas Pereira is set to complete a loan move to Lazio containing an option to buy, with their director of football Igli Tare claiming earlier this week that "Pereira will arrive in two to three days" and multiple Italian outlets reporting that he is set for a medical on Wednesday.
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Meanwhile, the club have a list of back-up options to Sancho that they will explore if their take-it-or-leave-it offer is rejected, with Bournemouth's David Brooks, Juventus winger Douglas Costa and the experienced Ivan Perisic among those being considered.
The possibility of signing teenage prospect Amad Traore is also being explored, although he is not being considered as an alternative to Sancho.