There was talk of his move to Benfica being completed like where former RM player Raul de Tomas went and performed so well. But Mariano seems determined to stay. He will not leave unless the club satisfies his demands.
Mariano, 'AS' says, earns more than four million euros a year, an amount of money which very few players can get at this moment in time. And that is what is preventing him from leaving Real Madrid.
According to the cited source, his financial demands are what are preventing him from leaving 'Los Blancos'. In fact, Benfica were going to get him on loan, but Mariano wanted more money and turned it down.
His agent turned down the move and Mariano is trying his very best to persuade Zidane to give him another likely. This is despite being told repeatedly that Zidane does not count on him.