The 24-year-old record signing was recently ruled out for several weeks due to a hamstring injury which Mourinho thinks is down to the player's incorrect decision to ignore the advice of the club medical staff.
Pogba sustained the injury during United’s 3-0 victory over Basel on Tuesday and, according to reports, chose to consult his personal trainer instead, something the United medical professionals think piled a few unnecessary weeks for the player on the sidelines.
The French midfielder will be out until the end of next month.
Questions over his temporary replacement have also arisen following reports in the Daily Mail that Mourinho had also fallen out with Ander Herrera.
According to the newspaper, Herrera earned an ear-beating from the Portuguese manager after deciding to bring a ‘friend’ with close links to Celta Vigo to the training grounds.
Despite the lack of understanding between the two, Mourinho is likely to throw Herrara a lifeline following Pogba’s injury.
United are currently sitting top of the table, undefeated in four league games.