Mourinho also went on to lament the absence of some of his key players due to injuries and other reasons.
"We play Real Madrid and we have no more players than what we have," he said.
"Antonio Valencia comes from holiday - I think too much holiday for him. His condition was not good when he was back, then injury and also go back.
"Anthony Martial has the baby and after the baby is born - beautiful baby, full of health, thank God - he should be here and he is not here. So we have Alexis [Sanchez] and [Juan] Mata who play every minute of every match and now we have Real Madrid and after that Bayern Munich and that's our start.
"I just hope the boys on deserved holidays, they take care of themselves a little bit and I hope somebody wants to do what [Marcus] Rashford and [Phil] Jones decide to do, which is to be back a little bit earlier to try and help the team because for the beginning of the season we are going to be in trouble.
"The majority of the players that played are not going to play - some of them are not even going to belong to the squad."