Well it’s not like Van Gaal hasn’t used it as an option before this season.
According to the Dutchman, Fellaini is a good target man given his height and ability in the air and in fairness to the flop turned valued member of the squad, he does score a few goals.
Fellaini is a viable option up top and you could even start him in his more natural position in the middle of the park and shove him forward if things are not working out or a goal is needed. He does cause problems for defenders and gives them a completely different headache than Falcao, Rooney or Wilson can.