I'm not saying Russell doesn't deserve the blame, but I think you have to also give credit to the dysfunctional Raiders as well.
Russell held out and missed TC, and that's on him (though he got paid a huge sum so you could argue it was worth it). But shouldn't the Raiders have had more of a framework for the deal in place before drafting him? They could negotiate with the #1 pick prior to the draft.
The team obviously wasn't good the year before since they were picking #1. Then they hire not just a rookie HC, but the youngest HC in the NFL in Lane Kiffin. Kiffin eventually ends up in one of the craziest power struggles with crazy old Al. Eventually he's replaced by Cable, who's a bit of a nutjob himself.
Russell didn't help by holding out, but eventually got to play in a few games, and started the last week. He threw two picks, lost a fumble, and got injured. For his rookie season, he completed 36 of 66 attempts for 373 yards, 2 TDs and 4 INTs and a 55.9 QBR. But after that game, Kiffin officially names him the starter for 2008. WTF.
And where was the veteran QB to help tutor? In 2007, he had Josh McCown and Andrew Walter. In 2008, they added Marques Tuiasosopo instead of McCown. In 2009, Charlie Frye, Bruce Gradkowski, and J.P. Losman.
Again, not excusing Russell entirely. No one force-fed him to balloon to 300 lbs. But I wonder how much of his failure can be traced back to the dysfunctional black hole that is the Raiders.