If you remove his two horrible games and work in averages for yards and touchdowns his numbers would look like this.
QB 77.4 rating 2,503 yrd 15 TD 11 INTs 56.9% comp
Joe Flacco who did basically the same thing Sanchez did his rookie season, when he made it to the conference finals
QB 80.3 rating 2,971 yrd 14 TD 12 INTs 60.% comp
And for shits and giggles Peyton Manning's rookie numbers
QB 71.2 rating 3,739 yrds 26 TD 28 INTs 56.7% comp
And Eli Manning's numbers
QB 55.4 rating 1,043 yrds 6 TD 11 INTS 55.4% comp
So while it's very possible Mark Sanchez sucks, at this point perspective and patience would be wise. I'm sure the opportunity to pile on the guy will come in a few weeks.