Then he needs a better agent, I guess. If he's an $8M player now, then he was most certainly an $8M player two years ago when he signed it. If he 'settled' for a $4M valuation of himself, then that's his own fault. And if he knew for sure he was going to increase his own worth over a two year span, then he should have made sure someone put some incentive clauses in the contract with escalators for performance or rankings.
And again, if this was something he was doing in the final year of his deal, then it would be a non-issue. But he's only 2 years into a 4 year deal that he himself negotiated while in the final year of his FIRST contract. Seriously, how many players get 3 contracts in 5 years? I think he's just pissed that everyone else around him (Wagner, Wilson, Sherman) are all getting fatter deals and he's jealous of their wallets.