Speculation about the midfielder's future is rife, with reports of interest from Barcelona, but Ferdinand has told executive vice-chairman Ed Woodward he must keep hold of the 25-year-old.
The Portuguese coach said the inability to train with a full squad could prove costly when United host Leicester City (Aug. 10) and visit Brighton & Hove Albion (Aug. 19) in their first two games of the new Premier League campaign.
United are without several World Cup participants, including France’s Paul Pogba, Belgium’s Romelu Lukaku and Marouane Fellaini, and England’s Jesse Lingard and Marcus Rashford among others.
The 19-year-old, who joined United on a five-year contract last month, sustained the injury while playing for former club FC Porto in the closing stages of last season.
Pogba was the subject of criticism from some quarters for his United performances last season and found himself relegated to the bench at times during the second half of the campaign.
Mourinho said favourites Brazil and Germany had the most balanced squads and he did not expect the World Cup to see a shock winner in Russia.
Manchester United manager Jose Mourinho hopes he gets the chance to face Arsene Wenger again after the outgoing Arsenal manager's final visit to Old Trafford as Gunners' boss ended in a 2-1 defeat on Sunday.
Pogba had scored two goals in a remarkable second-half recovery from United as they won the Manchester derby 3-2 to deny City a win that would have seen Pep Guardiola's men clinch the title.
Docherty knows what it takes to succeed at United after spending five years in charge in the 1970s and he doesn't believe Mourinho has the right stuff to thrive in Manchester.
United boss Mourinho admits his players must learn to cope with the pressure of expectations, a problem that has become all the more apparent in the wake of Tuesday's European setback.
Manchester United boss Jose Mourinho has the tough task of keeping Liverpool's Mohamed Salah quiet as Jurgen Klopp's entertainers roll into town at the weekend -- with second place in the Premier League the prize on offer.
Manchester United head coach José Mourinho’s brilliance puts him head and shoulders above other coaches.
The Portuguese says the 21-year-old played like a senior player, with great maturity, with tactical sense and a sense of responsibility.
The French midfielder, who cost United £89 million, hasn't completed 90 minutes in a month, with Jose Mourinho either substituting or benching him in the last few games.
The United manager says he has to come up with a contingency plan as the French midfielder may not be available for then trip to Sevilla.
Although the Portuguese is aware of Scott McTominay's abilities having utilised him in 12 games this season.
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