That's the thing that keeps getting missed.. Even though he's awful with turnovers he also must be the "luckiest" QB in the league. No other QB has as many balls dropped by the opposing defense. I doubt the data exists but if you combined actual turnovers with those dropped by defenders I bet Sanchez is in a league of his own with the number of potential/actual turnovers, far worse than the next QB on the list.
I'm convinced he doesn't throw a very catchable ball period. His passes get dropped by both the offense and defense.