Looking at the Jets as they enter the 2013 season, it's obvious that they have major holes and will not have money to throw around to fix them. However, one man needs to prove that he can be the coach of the future, while coping with a subpar roster. Hence, this is why Rex needs an "above expected" season.
Looking at this year, it was a disaster. Next year on paper the Jets have little money, plenty of holes, a solid draft pick, but not enough draft picks to really stock up. This leaves a huge problem with Rex, as he needs to win now even though his team may not be good enough.
So what would make the Jets keep Rex around assuming the GM doesn't hire one of his guys right away after this season?
Honestly, a playoff appearance would more than likely keep Rex around (assuming 9-7 gets you into the show.) If the Jets do make it to playoffs, with or without a deep run I think Rex gets another year. In 5 years, that would mean he got to two AFCCG appearances (losing one on a scramble) and a playoff appearance with a subpar group. Couple that with only one losing season and it's hard to let go of a coach with success. Look at Coughlin for example, he was ready for the axe in 07 until the run into the playoffs and SB and now he's one of the best coaches in the NFL. Giving a guy with success multiple years isn't unheard of, and frankly we talk about the lack of stability with the Jets. Giving him another season to prove he belongs in this case, shouldn't bring an argument, except from people who believe the Jets didn't achieve and should have been in the superbowl in 07 and 08. (I know some people may argue, but looking at the roster the last two years and 8-8 and 6-10 were right about projections.)
Any other scenerio depends on what the GM's definition of success is.
A winning season may also give Rex another year. Even an 8-8 with the roster may warrant some type of leniency. For a coach whose teams have suddenly not been able to preform, a winning or 500 could spell another year of Rex. As the roster is constructed now, objectively even with draft picks, there isn't many who expect the Jets to be competitive. Could this be the season a 500 year is acceptable? Maybe. Again depends on the GM. Still that would be very, very iffy.
Any other solution would mean the GM thinks the Jets are hopeless this year and anything other than a 4 win season is an accomplishment. This would scare me on a number of levels. This could mean a number of things: Is the talent simply not there, or did the GM do nothing to improve it, or despite the GM's approval is it the coaching that's not getting us there. There's a very minute chance this happens, but if it does, it really does look like dark times for the Jets.
In essence, Rex is left with a roster without much talent right now. But he has to win to prove it. Realistically it's playoffs or bust for him. Even if he gets a better than expected year, he still could be canned. It's a long shot but to prove he belongs, Rex must be the coach he think he is in 2013 to keep his job for 2014.