There could be a conspiracy theory here
Rod Thorn gave no indication he was retiring or taking time off whatever he calls it. Avery said in his press conference one of the reasons he took this job because he was looking foward to working along Rod Thorn. I feel like Mikhail Prokhorov was very sold on the fact that we would sign free agent at the time LeBron James. After no big free agents signed with the New Jersey Nets, Mikhail Prokhorov might have been displeased with Thorns lack of ability to bring in a top name. Prokhorov made it clear that he wants to win and he wants to win as soon as possible. I have a strong feeling he told Thorn "look you aren't helping my team improve at all so I am going to have to find a replacment."
Thorn hinted that he would have stayed if the Nets signed Lebron James. I think Thorn didn't want it to be known that Mikhail refused to offer him a new contract and asked Mikhail if he could leave out that part and say he is leaving on his own.
People are saying this entire thing seems fishy and I would have to agree with that.
My opinion Thorn was not offered a new contract