To be honest, I never really entertained the idea of Fellaini having an effect; but it happens so often that there's something to it. Fellaini when he comes on often plays as an auxillary striker which often opens up space for other players. He also has 4 goals in 12 apps which is good return for an impact player. He is so good with the long ball; that I wouldnt mind him staying. When we need a goal with 10 mins to go, bring on Fellaini and get him in the box to cause havoc. He can also do a job against the lower league teams that often rely on their physicality.