OK let me say that I'm actually a big Rondo fan, however... this wrist thing isn't looking good in a shortened season, we're playing great without him, and $37M in cap room is a different story from $25M.
So what if we trade Rondo + right to swap 1st rounders for Nash? Phoenix is a mess and bound for the lottery. Forget Gortat, he is their only building block at a premium position on a reasonable contract. They aren't moving him. But Nash, he needs a ring and IMO still has 2 or 3 years left in him, and he's healthy right now.
Next year, sing Howard and you would still have something like $17M-$20M to spend on bringing back Nash, Allen and Garnett for 1 more year, or replacing them. And we would have 5 young players from 2 drafts to start building around, with another load of cap room the following year.
Nash / Bradley
Allen / Phoenix lottery pick / Moore
Pierce / 1st rounder
Garnett / JJJ
Howard / veteran min