http://www.telegraph.co.uk/sport/fo...a-because-of-his-unprofessional-attitude.html
If this is true, then fair play to him for leaving. 100% not his fault. I think loyalty should be a 2-way street. When a player performs very well, then the club should have improved his contract. This is also the reason why Flamini left as well. The board were about to force Wenger to sell Flams to Birmingham (after he had a shit season), and he never got the new contract he wanted, so he played insanely well and left for free.
Imagine being one of the best players at the club and only being on 55k per week. Some of the benchwarmers were earning more than he was!