People make up new positions every single year, and question a players ability to play anywhere else with a whole host of insane reasons, like build or quality.
Here's a clue a very good player can play in pretty much any position, a great player could play any position. Pires could play either wing, in midfield, as a striker. If you're only good at crossing, you won't make a great defensive midfielder but could make a great winger, great players can be moved just about anywhere.
Fabregas has played, both wings, DM, central mid, AMC, striker and I have no doubt at all he could fill in at fullback should he need to.
Moura doesn't have the build to play in central mid, sorry but rubbish, Wilshire is tiny compared to a lot of players and there really wasn't anyone in the league he wasn't capable of bullying, size/height have zero bearing on how effectively you can use it. Hesky is a massive lump but hasn't used his size for years now.
Has Young played on the right? He's played all across midfield, anywhere upfront, and he's played plenty of games defending a crapload at Villa, of course he can play on the right.
There used to be left midfield, then there was left midfielder, attacking left midfielder, now we've added wide striker, and somehow people want to pretend this is a completely different position to their right hand versions as well. It's like people want a new name depending on the square metre of pitch you spend the most time in. Get over it people. If Moura is good enough there won't be an attacking position he wouldn't be capable of playing in.
This all ignores the fact that just because team A plays him in a position doesn't mean its his best position or his only position, its normally not much more than how the team works best.
It's even more funny when most of the people on here(me included) have barely seen him play.
hernandez can't play another position because he's pretty rubbish in most aspects of his game, tap in's, sure, speed, sure, footballing genius... not even close. Rooney has played both wings, deep/upfront striker, midfield. Gigg's has played the same positions, Scholes is really lacking the pace to play wide but has played really everywhere down the middle, Young has played all those positions too, as has Nani.
