Darnold (undisclosed) limped to the locker room during the first quarter of Sunday's game at Buffalo, Brian Costello of the New York Post reports.
After missing three contests with a sprained right foot, Darnold was cleared to return Sunday, only to last nine minutes before suffering a lower-body injury. It remains to be seen if his right foot is the culprit, but the Jets will confirm the nature of the injury in short order.