Dart is believed to have suffered a sprained MCL in his left knee during Monday's 28-6 loss to the Rams, Ian Rapoport of NFL Network reports.
Dart underwent X-rays that were returned negative, and an MRI scheduled for Tuesday should either confirm or negate the initial diagnosis of an MCL sprain. The promising young quarterback logged just one offensive series Monday before getting hurt while throwing a third-down pass. Per Rapoport, Dart is expected to miss "some time," though he will likely be able to return this season if the injury is limited to a sprained MCL and no other ligament damage. In the likely scenario that Dart ends up missing games, Jameis Winston will be lined up to work as New York's starting quarterback.