4) What to do with Rooney?
One of the biggest challenges Mourinho still has to face is the question of Rooney. The England and Manchester United captain had a brief foray in midfield at the end of the last season.
Since then, he has been restored to his number 10 position in both club and country. However, if United switch to a 4-3-3, where does that leave Rooney?
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It seems impractical to play him on the wing ahead of Young, Lingard, Memphis, Martial and Rashford. And that is not even considering the claims of Mata and Mkhitaryan.
The only other option is to play him in midfield. But there too there are contenders aplenty in the form of Carrick, Fellaini, Herrerra, Schneiderlin and Pogba.
When all is said and done, Rooney could turn out to be the biggest casualty in the long run.