I guess the bottom line was that they didn't have a spot for him with the change of defensive philosophy, which puts more DBs on the field instead of customary three LBs.

Also, the young LB in their roster was viewed as a straight replacement if not an upgrade over him.

Dolphins were probably going to cut him if they couldn't have found a trading partner. With the trade they only have to pay 1M$ of his salary and are off the hook while also getting a promising young ST contributor in exchange.

It wasn't a bad deal for Miami even though it might seem like it from our point of view.