He earned at least a one year grace period after last season. The Jets won't fire him after this year even if he goes 4-12.
The Jets get to play the horrible NFC East as their cross-conference opponents. You can pencil in 2 wins against the Giants and Eagles right now--the Giants' defense is absolutely putrid, and McNabb can't hit the broad side of a barn any longer.
And they'll do no worse than split with Miami and Buffalo.