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.
According to the Mirror, Manchester United are the latest team to enter the race for Dembele - alongside the Gunners.
It's not a great time to be a Manchester United fan as manager Jose Mourinho has been causing some kind of irritation and uneasiness at the club. It is understood that the hard relationship between Mourinho and his 25-year-old star has become tense once again, however.
Former United defender Rio Ferdinand, meanwhile, fears Mourinho's summer sulk will destabilise Manchester United's season.More news: Pakistan poll results threaten Imran Khan's premiership
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Mourinho is keen to bolster United's attacking options ahead of Thursday's transfer deadline, with Inter Milan's Croatia star Ivan Perisic also reportedly a target.
Mourinho appeared to question Pogba's effort and heart while playing for his club, saying, "I don't think it's about us getting the best out of him [at Manchester United], it's about him giving the best he has to give".
Martial, on the other hand, has been linked with a move away all summer after his agent stated he wanted to leave Old Trafford back in June.
He goes on to report that United do not want to sell the "important" player as they see him as the franchise of the club. The Catalan club are working on deals to sell Aleix Vidal, Yerry Mina, Andre Gomes and Paco Alcacer to raise the funds to bring in the World Cup victor.