Cromartie did not practice Friday and had been officially considered a game-time decision, according to Jets coach Rex Ryan.
Cromartie has not missed a game due to injury in his three-plus seasons with the Jets. The two-time Pro Bowler told some teammates on Friday morning that he expects to play against the winless Steelers, a source told ESPN.com.
Cromartie's injury, being called a hyperextension, occurred during the portion of Thursday's practice closed to the media. Ryan revealed that it was a non-contact injury and referred to the situation as "one of those hold-your-breath type deals."
The 29-year-old Cromartie has been a key player in the secondary for the Jets, who enter Sunday with the NFL's second-ranked defense in terms of average yards allowed.
The Jets need Cromartie, an eight-year veteran, to help slow down Ben Roethlisberger and the Steelers, who boast the NFL's sixth-ranked passing offense.
ESPN NFL Insider Adam Schefter, ESPN.com Jets reporter Rich Cimini and ESPNNewYork.com's Kieran Darcy contributed to this report.