Smith (knee) is believed to have suffered a torn ACL, NFL.com's Ian Rapoport reports.
Smith was initially thought to have avoided a serious injury, but the initial results of Monday's MRI are believed to suggest otherwise. To pin down a definitive diagnosis, Smith will visit Dr. James Andrew on Tuesday, ESPN's Adam Schefter reports. If a torn ACL is confirmed, Smith would miss the remainder of this season, paving the way for Ryan Fitzpatrick to reclaim the Jets' starting quarterback job.