Link: http://sportsillustrated.cnn.com/2009/writers/ross_tucker/09/08/contracts/index.html

...are explored in this article by former NFL player Ross Tucker, where he explains, that while fans are only too willing to come down hard on players who demand that their contracts be re-negotiated, the reverse is often true:

I received a call from an active player around 10 a.m. last Saturday, the day teams reduced their roster to 53. His team had just informed him (via his agent) that he would be released if he didn't agree to a significant pay cut. The player had about two hours to think it over and get back to his organization. No pressure, right?

...Most fans dislike when players sit out OTAs or training camp while angling for a new contract. The consensus seems to be that players should honor their signed deals. That's a fine thought, of course, but in this case, which party isn't honoring the long-term contract? As it stands, I think these conversations happen more often than we realize, they just aren't publicized.

As Tucker explains, the gambit of demanding that a player reduce his salary or be released has been played a number of times by teams in this off-season. When you add to that the fact that a team can cut a player at any time (if it can absorb the cap hit), the deck suddenly does not look to be stacked in the favour of the players.
Tucker's musing hits the big issue:

...I think the time will come when a player takes the next step in the game of leverage that is constantly being waged between front offices and players. If a player wants his outdated contract redone or, better yet, wants the team to cut him and put him on the lucrative free-agent market, then withholding services for a regular season or playoff game is the biggest card a player can play.

Will it happen this year? Maybe not. Will it happen soon. I think it will.