Just FYI, since it hasn't been mentioned in this thread so far:
Danny confirmed in an interview a couple of months ago that Pierce's contract has a trade kicker.
He did not say what that kicker is.
My bet is that it may make the entire contract guaranteed. That is speculation, but it is a reasonable one, imho.
Also, at least 2 sites (BBR, Roto) that have contract info indicate that Pierce has a player option. Other sites do not indicate whether he does or doesn't.
One article about the contract (Boston Herald) that came out when he signed it indicated 'mutual options' but multiple options aren't allowed by the CBA. Of course, a player option combined with a 'partially guaranteed' salary structure like Pierce's is sort of like having mutual options, so maybe that's what it meant.
Anyways - the point of the above is just some food for thought. The net net of all that too me is mainly that these things make it harder to trade Pierce unless he wants to be traded.
His contract IS eligible for amnesty. I doubt that happens unless the moon falls out of the sky.
His contract is also eligible for restructuring. An option not discussed on this thread that I think is realistically possible is that they simply restructure his contract. They could drop his annual salary to ~11M and extend him another year. That would raise the total contract value from 15.7M to 22M. Make the entire thing guaranteed. For Pierce, that's getting more guaranteed money and definite path to retiring with the Cs. For the C's, they would drop their cap hit about 3.7M (giving Danny more room under the hard cap and saving more luxury tax money) and they'd effectively get Pierce for one more year for just over 6M.
This would mean Pierce' contract would terminate at the same time as that of KG, Lee, Bass, Terry - so Danny would have max flexibility to completely restructure the team.
Having Pierce' contract expire next year just doesn't really do much since by itself, it doesn't get us under the cap and there are no good trade targets for Pierce's expiring contract right now. I'd rather hold on to it until it can be combined with all the others.