His contract with City takes him to June 2015.
In a negotiation it is always key to recognise your own and the other party's strengths and weaknesses. It's hardly rocket science.
What is Mario's Achilles Heel? What is his raison d'etre? Playing for his country. It gives him a sense of personal vindication, which given his upbringing is entirely understandable.
A year on the sidelines would surely hamper his international chances.
The thought of missing out on a World Cup, and one in Brazil at that, would fill Mario with terror, for all his macho posturing.
If he pushes things too far, don't be surprised if that is a test that is applied to his resolve.