The Bundesliga challengers have stated on multiple occasions that they will be keeping the 20-year-old for another season, which has forced the Red Devils to look elsewhere after an initial bid rejected.
That has led to a possible loan deal for Barcelona winger Ousmane Dembele, who is said to have been involved in positive talks with international team-mate Paul Pogba over a potential move to Old Trafford.
In addition, forward Lucas Ocampos has emerged as another option, with Sevilla willing to talk.
ESPN have reported that although United could end up paying £45m to sign 23-year-old Dembele, they could decide to spend slightly less on former Marseille and Monaco man Ocampos.
The club are also said to have completed ‘extensive checks’ on his skill set and temperament.
They add that the 26-year-old could cost £36m with the Europa League winners willing to listen to offers for the Argentina international, who can play in multiple positions across the front three.
Ocampos scored an impressive 17 goals in all competitions last season as Sevilla finished fourth in La Liga, with Sancho managing 20 for Dortmund and Dembele only scoring once due to injury.
Ole Gunnar Solskjaer said of his transfer plans in a chat with talkSPORT this week: “You never know in football.
"You’re never surprised if anything pops up.
“We get speculation about us all the time. The club is working hard do what we want to do.
“I’m focused on the players we’ve got, ready for Sunday [against Tottenham], playing. That’s the sole focus in the coaches office."
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Both the alternative options to Sancho would cost less than half of his £108m price tag on a permanent deal, with Ed Woodward mentioning his financial limitations as recently as last month.
He wrote: "Disruption from the pandemic is continuing to create huge economic pressures from the top to the bottom of the football pyramid and, while we are fortunate to be in a more resilient position than most clubs, we are not immune from the impact.”
Before adding: “We must also be responsible in our use of resources during the most extraordinarily challenging time for everyone in football.”