#2 Provide legs on the wings
Just like the left wing, the right wing in the Liverpool game was not very effective. Matteo Darmian was very poor as a wing back and considering that Chris Smalling might not recover in time to start the next game, Mourinho needs to shuffle his defence to provide rigidity in the middle and fluency along the sides.
Since Mourinho does not have too many out and out wingers, he will be looking for his full backs to provide width down the sides. If he sticks to a 3-5-2, Darmian would be better off as one of the three centerbacks. That way, his lack of speed will not be highlighted and he will have Eric Bailly to cover for him. And in the Italian’s place, Mourinho should contemplate using Timothy Fosu-Mensah.
Fosu-Mensah has the speed and strength to emulate Antonio Valencia, who is injured and might not return in time for the opener against Leicester City. As such, the youngster should start as a full back, instead of as a centre back. He has the defensive core that Mourinho desires and his pace will pin back the opposition defense and he might even capitalize on the spaces that open up in the counter. Also, like Luke Shaw, he will be an option for the midfield to spread the ball and he should do a better job than the static Darmian on the flanks.