(NewsNation) — After Buffalo Bills safety Damar Hamlin went into cardiac arrest on the field during a game, a spotlight has been turned on the NFL’s safety plans for player injuries.

The NFL has had serious injuries happen to players before and the league’s health and safety guidelines have evolved over time. Most recently, changes have been made to concussion protocols and the timeframe for when a player is eligible to reenter the game after hits to the head.

The NFL also requires all teams have an emergency action plan that they rehearse prior to the season, which can be activated if a player is severely injured. Part of that plan includes identifying a nearby level one trauma center and having an ambulance and airway management physician on hand. The NFL says plans are gone over weekly during the season.

Hamlin collapsed after a routine play, and doctors have speculated that his cardiac arrest could be attributed to a condition called commotio cordis, which is a change in heart rhythm due to a blow to the chest or the result of a traumatic brain injury from a hit on his jaw.

Hamlin was on the field for around 19 minutes as medical personnel attended to him and performed CPR before he was transported by ambulance. That could have a big impact on his chances for recovery, as could the fact that his heartbeat was reportedly restored within 9 minutes, while he was still on the field.

Hamlin is still in critical condition, but cardiologist Dr. Dave Montgomery told NewsNation he’s seen patients in worse shape recover. Montgomery said he’s seen patients who received CPR for much longer than Hamlin recover.

“But there’s a lot to say here about the human will to live and the body’s own ability to heal itself. I just have to say this: Time will tell. We really just have to wait to see what his recovery is going to be like, and we might be surprised,” he said.

It took the NFL an hour to officially suspend the game, and some reports say the league was going to keep playing but players and coaches refused.

The NFL denied those claims and said the delay in suspending the game was because of time it took to communicate with the coaches and relevant officials.

“I’m not sure where that came from,” Troy Vincent, the league’s executive vice president for football operations said. “It never crossed our mind to talk about warming up to resume play. That’s ridiculous. That’s insensitive. That’s not a place we should ever be in.”

Still, seeing a teammate collapse can be traumatizing for players. Retired NFL player Ken Jenkins said an incident like Hamlin’s is a reminder that football can be a dangerous sport.

“I do think though, we have to commend the NFL for its emergency response teams and organized response to this particular incident. They had well trained folks on the sidelines on both teams, and they have the ambulances ready to go.” Jenkins said.

As hard as it might be, Jenkins said he expects Hamlin’s teammates will all be back on the field for the team’s next game.

they’re professionals and they’ll eventually have to get back on the field. It’s going to be difficult. Yes. And they’re going to be thinking about and they’re probably going to worry,” Jenkins said. “But they’re going to go back and they’re going to play.”

The Bills-Bengals game will not be resumed this week and the NFL has yet to set a date for the remainder of the game to be played. Hamlin’s family said he remains in critical condition in the ICU but his condition is moving in a “positive direction.”

The Associated Press contributed to this report.