Marouane Fellaini Must Adapt to a New Challenge at Manchester United

David Moyes invested a lot of money in Marouane Fellaini this summer.

He also invested a lot of faith and a small part of his reputation. Fellaini will always be the first signing Moyes made as Manchester United's manager. And, at nearly £30m, he didn't come cheap.

But the size of the fee isn't Fellaini's fault. He had no control over what United and Moyes were willing to pay.

It shouldn't bother him that his £27.5m price tag was more a reflection of United's desperate need for the central midfielder rather than his own talent.

But that's not going to stop fans from remembering that every time he misplaces a pass or looks like he's running with a grand piano on his back, he's United's fourth most expensive player.

Fellaini has not become a bad player overnight. He's played in the Premier League with Everton for five years and regularly starts for Belgium, one of the most talented national teams in the world.

United fans will say that's all very well, but they haven't seen the evidence for themselves.

And who's to blame for that? Has Fellaini played poorly since arriving on deadline day? Or is it Moyes' fault for not masterminding a system that suits his star signing?

The answer is probably a bit of both.

United fans have seen Fellaini play well twice against their team.

In the 4-4 draw at Old Trafford, which cost United the 2012 title, Fellaini was in a midfield which included Darron Gibson, Phil Neville, Leon Osman and Steven Pienaar, with Nikica Jelavic as a lone striker. In the 1-0 defeat at Goodison Park at the start of last season, Everton fielded exactly the same front six.

But in Fellaini's four starts for United, he's played in a midfield two with Michael Carrick each time. And without the insurance of an extra body in the centre of the pitch, his limitations—his range of passing and mobility—have been exposed.

The problem for Moyes is that his two most dangerous players are Wayne Rooney and Robin van Persie, and he wants both to play centrally instead of being an extra midfielder.

So, what happens now?

Fellaini has been an unused substitute in the last two games he's been available for. And paying top whack for a player to sit on the bench all season wasn't part of the plan.

Simply put, Fellaini must adapt or face the axe.

He will have to adapt to a new system at United, one which hasn't been designed for his specific strengths. If he can form a working relationship with Carrick, Rooney and Van Persie, United's prospects look a lot brighter.

But if he continues to struggle, Moyes will be forced back into the transfer market for someone who is a better fit—perhaps Ander Herrera, or, more ambitiously, Ilkay Gundogan or Sami Khedira.

United need a central midfielder, and Fellaini will get the first chance to prove he's the one. But Moyes is under enough pressure as it is without persevering with a player he might not be able to fit in.