Midway through the first quarter, Hamlin took a hard knock on a tackle, got up and then collapsed to the ground.
He received medical attention for more than 30 minutes, with ESPN reporting that he received CPR.
Players from both NFL teams gathered around Hamlin during treatment, many kneeling in prayer and some openly crying.
Image credit: NFL
The crowd in Cincinnati remained silent and television coverage broke away from the scene on the court.
ESPN said Hamlin, 24, was given oxygen as he left after being placed on a stretcher and his family, watching the game, joined him in the ambulance.
Reports said Hamlin was taken to the University of Cincinnati Medical Center, about four miles (six kilometers) away.
After the ambulance left the pitch, reports initially suggested play would resume after a five-minute warm-up.
But once the coaches of both teams spoke to the referees, the players were told to head to the dressing rooms, while the match was announced as “temporarily suspended”.
The NFL then released a statement saying league commissioner Roger Goodell announced the game had been postponed and gave details of Hamlin’s condition.
“Hamlin received immediate on-field medical attention from the team and independent medical personnel and local paramedics. He was subsequently transported to a local hospital where he is in critical condition,” the league said in a statement. a statement.
“Our thoughts are with Damar and the Buffalo Bills. We will provide more information as it becomes available,” the NFL added.
“The NFL is in constant communication with the NFL Players Association which has agreed to postpone the game,” the statement concluded.
The thoughts and prayers of all the Bills Mafia are with you, Damar. 🙏 https://t.co/lDWNAOEPX4
— Buffalo Bills (@BuffaloBills) 1672712171000
ESPN analyst Booger McFarland, a former NFL player, called on the league to scrap the game pending a decision.
“Nobody cares about football at the moment…they care about one thing, the health and safety of this young man,” he said.
Video footage showed Hamlin had been hit in the upper chest area.
The NFL, one of the most violent team sports, has faced growing concerns in recent years about player concussions from blows to the head.
