I think as long as the QB isn't put into a position where he has to do too much, the Jets will be in games because of their defense. Mark was a mess last year trying to do too much down the field, but he also didn't have any weapons at all. I've liked Chris Ivory, he was really stuck behind some other talented RBs in New Orleans...if he can stay healthy and get 15 productive carries a game, and Powell takes a step forward as well, the Jets can play relatively conservative offensively by pounding the football and be in games in the 4th quarter.
That said, I have them at 6-10 this year. But there are winnable games early. If they started 3-1, it wouldn't shock me, and then maybe they'll have some confidence moving forward.