Rondo's trade value was never that high to begin with. We've been trying to trade him for years and supposedly we have been turned down several times (Pau Gasol, Steph Curry, Chris Paul)...
He's a great point guard, but I imagine most teams are looking for an impact scorer or a dominant big man. Guys who can pass great, but can't score don't tend to fetch as much... probably why Jason Kidd was traded multiple times despite being a rich man's Rondo in his prime.
I can't imagine him having much trade value at all now... the possibility of him never returning to 100%. Nobody would take that risk.
Too bad... I wonder if the Seattle group were to take over the Kings before the deadline if they'd consider moving Cousins and their bad contracts for Rondo. If they were confident in Rondo getting healthy, they could trade for him and tank while he heals.