If we decide to trade Pierce (I'm personally in the run it back camp):

Boston trades:  Pierce, Shavlik Randolph, future 2nd rd pick
Memphis trades:  Ed Davis, Tayshaun Prince, Donte Green, 2015 1st

I think it should be obvious to Memphis that they missed a lot what Rudy gave them in the playoffs and Pierce can give them that.  Shav is a replacement 4th big for Davis, who Memphis clearly doesn't trust with playoff minutes yet and only gave 15mpg in the reg season even.

For the celtics, Tayshaun is not on a good contract, but if we trade Pierce, we're not contending this season anyways and Tayshaun's contract becomes an expiring $7M next summer.  That expiring $7M, Ed Davis, and a first round pick are all assets that could be useful in moving to another team in a package for a big time player.

*I can't tell if this trade works or not as is because Trade Machine hasn't updated to next season's salaries (where Pierce's decreases and the Grizzlies all increase).  I think it may be off by 1-2 million, which can probably be made up with smaller pieces like Jon Leuer and a 2nd round player or min contract)