He was also a rookie that first year so its a bit unfair to cite accuracy. You will note I said"star" QB. Sanchez never was and seldom performed well. The team was great: he wasn't. BUT look at his play this year. overall he looks much improved BUT against the only good team he has faced and was hit and bothered, he lost. More hits will be coming as he plays better teams. The book is still open regarding Sanchez. Against poorer teams with no pass rush he looks much improved.
I maintain that NO QB can pass when they are on their backs or running for their life consistently.