So anytime a player decides he wants to leave or there is interest from another club, he should get a pay rise.
Anytime a player performs well for a while, he should get a pay rise, even if he has 3-4 years left on his conract.
Yet, I don't remember many instances when a player signed a fat contract, played like crap and went to the club and said, "Listen, I've been complete garbage, let's lower my wage."
Something is seriously wrong with football, if a club can't tell a player to respect his contract anymore.