The Red Devils have been consistently linked with a move for the Borussia Dortmund star though have refused to meet the £108m valuation.
United missed a deadline that Dortmund set last month though the Old Trafford outfit are not giving up hope just yet.
Some of United’s squad numbers for the new season was announced last week with new signing Donny van de Beek taking No. 34 and Mason Greenwood the new No. 11.
The famous No. 7 jersey, previously worn by the likes of Eric Cantona, David Beckham, and Cristiano Ronaldo, was left vacant though.
And ESPN claim that it has been left available in the hope that Sancho may still arrive before the transfer deadline on October 5.
Alexis Sanchez had been given the No. 7 shirt following his 2018 move from Arsenal though the Chilean struggled at Old Trafford and has now left.
Though Rio Ferdinand believes Sancho should take the shirt despite Sanchez’s poor performances in it.
Ferdinand said: “Yes, I would [give Sancho No 7], he’s that type of character.
“He’s got an arrogance about him, it’s what you want on a football pitch, they’d embrace that.
“So yes, I’d give it to him and put that pressure right on his shoulders!”
Van de Beek is United’s only transfer of the summer to date though they are expected to make more moves.
Boss Ole Gunnar Solskjaer recently said: “I cannot say when or if transfers will be done but we are looking at it and we’ll have to sit down because it’s a quick turnaround.
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‘We’ve got to be 100 per cent sure when we make those deals. It’s going to be a strange summer. We’ve only got a couple weeks away from each other until we get going again.
“That’s going to be a mental challenge. Of course, we’ll keep pushing and keep demanding more of players we have but we’re looking to improve.
“It’s a strange one. The league starts very quickly but the market’s open for so long. We’ve got to be good smart and clever.”