Passer Rating -- Mark Sanchez had five games (SFO, HOU, SEA, ARI, TEN) with a passer rating under 55.
Turnovers -- Sanchez had nine games (@MIA, SFO, HOU, @NWE, MIA, SEA, NWE, ARI, TEN) in which he committed more than one turnover via interception or fumble lost.
Completion Percentage -- Of his fourteen starts, Sanchez had six games (BUF, IND, @NWE, STL, NWE, JAC) where he completed more than 60% of his passes.
Scoring -- Sanchez had more games (four - SFO, SEA, ARI, JAC) where he scored no touchdowns with his hands or feet than games he scored more than one touchdown (two - BUF, IND)
So how does that all stack up? I would have added Football Outsiders, but since their site has been down for two days ...
Pro Football Focus: Sanchez is ranked #34th among all 2012 quarterbacks - putting him in the company of players like Michael Vick, Christian Ponder, John Skelton and Ryan Fitzpatrick.
Advanced Football Statistics: Sanchez is ranked 39th among all 2012 quarterbacks - the last player on their list behind Ryan Lindley and John Skelton.