http://articles.businessinsider.com/...-orlando-magic
The story is, he signed the extension to avoid being traded to the lakers. I guess the Magic wanted more time to get the best deal? I guess Howard felt that extending the mess gave Brooklyn a better window to allocate resources?
If im the lakers, I still think that, with Nash running things, once he gets a taste of the spotlight he'd stay in LA. For that extra cash, too.
But I think the best explanation for the opt-in, is that the Magic felt the full year gave them more leverage in a trade; and Dwight, knowing the Lakers wouldnt send him where he wanted, opted in, and hoped the Magic and Brooklyn would figure something out.