The 24-year-old Bills defensive back briefly got to his feet after making what appeared to be a routine tackle on Bengals receiver Tee Higgins with five minutes and 58 seconds remaining in the first quarter but then collapsed to the ground.

The game in Cincinnati was halted as medical staff quickly attended to him while players from both teams took a knee. The NFL later announced the game had been postponed.

As Hamlin was taken to the hospital at 9.25pm local time, players from both teams went to their locker rooms, some with tears in their eyes.

"Hamlin received immediate medical attention on the field by team and independent medical staff and local paramedics," NFL commissioner Roger Goodell said in a statement.

"He was then transported to a local hospital where he is in critical condition.

"Our thoughts are with Damar and the Buffalo Bills. We will provide more information as it becomes available."