I thought his game dropped off after he did his knee.

My guess is that he could see the writing on the wall, with youngsters like Astbury, Gourdis and Grimes pushing him further and further back in the pecking order over time.
Has been a very serviceable player, but I dont think he has recaptured what he was showing before he did his knee. If he goes elsewhere and finds greener pastures then good luck to him. Hopefully it will be a win win situation.