Well...it's kind of hard to evaluate a rookie who takes over the starting QB for a team with a make shift offensive line and limited offensive weapons like CJ did with San Fran. Most rookies playing in that environment isn't going to do well. Jimmy G. came to SF with three years playing behind one of the best QBs in NFL history. He had a three year learning curve. You can't compare them...it's not fair to CJ.
Now, if you put CJ as a starter now with the offensive line and weapons they have now in SF...it's a much different ball game and I think things would be terribly different. He will get his chance.
I think in CJ's 2nd year with the 9ers he won a couple of games as the starter. He is no slouch but just needs a chance and lots of reps with 4-6 starts to see and show that he has the right stuff.