KingMessi
SiempreBlaugrana
Messi was also a winger. Then he was a false 9 and now people want him to be a CAM, or even a second striker. It is the qualities that matter, they are the ones that make a player suitable to play in a certain position.
The transition from winger to fullback is not the same as from winger to center forward.
And before you bring it up, yeah Alba was a winger before he was converted to leftback at Valencia, but right now we need defensive stability, and two attacking fullbacks won't bring us that. DonAndres's post here earlier summed it up very nicely.