Paul Pogba is willing to join Manchester United but only if his first choice of Real Madrid proves impossible.
United is willing to meet Pogba's wage demand of €300,000 per week.
Juventus is asking for a minimum transfer fee of €100 million.
Pogba's agent Mino Raiola brokered the deal for Mourinho to sign Zlatan Ibrahimovic, who is also a client, on a free transfer.
Mourinho officially began working at United on Monday in advance of his official unveiling at the club on Tuesday.