Petty is expected to start Sunday against the Rams, according to ESPN's Adam Schefter.
Ryan Fitzpatrick was limited in practice all week because of a knee injury, and while the Jets were apparently going to let him see how his knee felt in pre-game warmups, the decision has apparently been made to have Petty under center. Given Fitzpatrick's struggles through most of this season, it's possible that the Jets could continue to go with Petty if he performs well Sunday.