Wednesdays are usually the main day for teams to implement their gameplan, so the fact that QB Mark Sanchez was not out on the field does not bode well for his chances to play this Sunday. He was spotted on the stationary bike not dressed for practice.
Sanchez already has a brace on his left knee since college. If he were to somehow play Sunday, he would have to put one on his right knee as well. But he hasn't been participating in practice thus far this week, so it's looking less and less likely.
Even though Sanchez needs experience, and the Jets are in the thick of the playoff chase, if Sanchez is risking any serious complications, he should not play on Sunday. Fellow rookie QB Matthew Stafford impressed fans with his toughness, playing on Thanksgiving with a separated shoulder, but knee injuries are tricky, and while right now the prognosis is positive, one bad hit, and Sanchez could be out 10 months.