Manchester United are fearful of their first team manager Jose Mourinho going into meltdown, as a result of his trusty number two Rui Faria departing his side for the first time since 2002.
As reported by the Daily Star, the Red Devils are wary of the impact of Faria's departure from Old Trafford for 'family reasons', with his and Mourinho's trusty partnership dating back to the early 2000s.
A source close to the club said: “Rui was the only person prepared to stand up to Jose in the past and talk some sense into him at times. They were best mates and inseparable.
“Even this could lead to fall-outs, but Jose respected him more than anyone else. Now Rui has gone and isn’t by his side, who knows what could happen? Jose is off the leash and who is going to control him?”
The 55-year-old has made no secret of his failing relationship with star players Anthony Martial and Paul Pogba, publicly criticising the pair on numerous occasions.
Additionally, Mourinho is also struggling to get along with executive vice chairman Ed Woodward, after he decided not to pursue the United boss' top targets this summer due to disagreements over their value.
Woodward has allowed Mourinho to spend over £392m in just two years, with none of his signings proving to be real hits with the Old Trafford faithful.
Woodward's concerns are justified, given Mourinho's troubles working with the club's record transfer, Pogba, whilst also struggling to get the best out of £60m duo Eric Bailly and Victor Lindelof.