Five minutes and fifty-eight seconds into the first quarter of a hotly anticipated showdown between the Buffalo Bills and Cincinnati Bengals, two streaking teams looking to finish the season with a signature victory, players stopped playing and started praying. 

The occasion for beseeching Monday night was an injury to a Bills player, Damar Hamlin, a second-year safety out of the University of Pittsburgh. Mr. Hamlin attempted to tackle a Bengals wide receiver, Tee Higgins, falling to the ground in the process. The defender got up and started walking, only to wobble and collapse. 

Mr. Hamlin did not get up again. Medical personnel administered CPR as coaches and players knelt in prayer and weeped on the sidelines. The two head coaches — Sean McDermott and Zac Taylor — conferred with the referees, and then led their teams back to the locker room. The game was suspended indefinitely.  

A Hall of Fame former quarterback and who is an analyst for ESPN, Troy Aikman, called the scene “unprecedented” and averred that he had “never seen anything like it.” 

Mr. Hamlin was taken to the University of Cincinnati Medical Center in an ambulance along with his mother. The Associated Press reported that he is in critical condition and that the Bills said he suffered cardiac arrest on the field. In a statement, the NFL said its thoughts are with “Damar and the Buffalo Bills.” 

“Damar Hamlin suffered a cardiac arrest following a hit in our game versus the Bengals. His heartbeat was restored on the field and he was transferred to the UC Medical Center for further testing and treatment,” the Bills said in a statement, according to the AP. “He is currently sedated and listed in critical condition.”

This is not the first time this season that an NFL field has been the site of a seemingly serious injury. A quarterback for the Miami Dolphins, Tua Tagovailoa, has repeatedly exhibited concussion-induced symptoms on the field, including stiffened fingers after a head injury in October.

After that injury, the NFL altered its protocols to add a diagnosis of “ataxia” to the mandatory “no-go” symptoms that determine whether a player is allowed to re-enter a game.  The Mayo Clinic defines ataxia as “poor muscle control that causes clumsy voluntary movements,” usually caused by damage to the cerebellum.

In 1991, an offensive lineman for the Detroit Lions, Michael “Mike” Utley, was paralyzed from the chest down when he injured his sixth and seventh cervical vertebrae.