How bad was JaMarcus Russell in the 2009 season?

My friends are arguing with me saying that JaMarcus Russell wasn't the biggest problem the Oakland Raiders had last year. I watched every football game religiously and when JaMarcus was on the field our offense looked horrendous, our offense didn't stand a chance in my opinion. I don't think Bruce Gradkowski or Charlie Frye our starting Quarterbacks in this league but I do feel that our offense looked WAY better under them than JaMarcus Russell. Our defense even looked better because the offense could pick up a couple of first downs. Overall I feel that JaMarcus was our main problem last year, I know we aren't the best team but I feel that JaMarcus was our weakest link. If their is anybody who is a Raider fan and watched all of our games or if their is someone who just watched a lot of our games, would you be kind enough to just shed some light on this topic so I can convince my friends otherwise??