#1 Romelu Lukaku
This burly Belgian striker has been the biggest culprit of United's slump. Lukaku could easily score 30 goals for Everton in a tough season, but now he has added weight and can barely get basic things like ball control done. Ever since he scored 4 goals in the opening 5 games, he has undergone a serious goal drought.
At Old Trafford, the place where United's powers should come alive, he has gone on a dry spell since March at the stadium. Mourinho for sometime chose to continue playing the Belgian despite his poor form. An injury to Lukaku forced the manager to change tactics and the team started playing better.
Since his return, he has chased shadows as United lost 3-1 to Manchester City, and had a disappointing 0-0 home draw against Crystal Palace. This begs the question, should Lukaku really be a starter at United?
Based on his performance and overall contribution, he should have a merciful place on the bench at most, and could be brought on as substitute reinforcement.