Manchester United are concerned about Jose Mourinhos state of mind following Rui Farias surprise decision to step down as assistant manager.
Mourinhos working relationship with Faria dated back to 2002 but family reasons convinced the latter to quit United after last seasons FA Cup final defeat to Chelsea.
Faria followed Mourinho from Porto to United – via Chelsea, Inter Milan and Real Madrid – and Uniteds hierarchy fear that a change in personnel in the Old Trafford dugout is having a negative impact this term.
Michael Carrick and Kieran McKenna were both added to Uniteds first-team coaching staff in the summer but it appears Mourinho is still recovering from Farias departure.
A club source told Starsport: 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 isnt by his side, who knows what could happen? Jose is off the leash and who is going to control him?
Mourinho made no secret of his unhappiness with Uniteds board and executive vice-chairman Ed Woodward this summer as the club failed to bring in a top-class central defender.
Reports earlier this month also claimed Mourinho was involved in a bust-up with Paul Pogba over the Frenchmans future.
The Portuguese is understood to have told Pogba to hand in a transfer request if he wishes to leave amid speculation that Barcelona are interested in signing the midfielder.
Pogba hinted at a rift with Mourinho after Uniteds victory over Leicester, stating: There are things that I cannot say otherwise I will get fined.