On Tuesday, for the first time, one of his teammates spoke out.
"This is just something that should wake up everybody, that not every situation is promised," said Dion Dawkins, Bills lineman and former Temple University standout.
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And in its aftermath, the nonprofit Simon's Heart is trying to raise awareness that sudden cardiac arrest is the number one cause of death among student-athletes.
"We know kids that have been in the exact same position that Damar was in last night and passed away, unfortunately," said Executive Director Jenn Parrado. "And we're hopeful because we also know families that have survived and a lot of adults that have survived sudden cardiac arrest because there were people in the right place at the right time to protect their heart."
SEE ALSO: Buffalo Bills' safety Damar Hamlin remains in critical condition after cardiac arrest on field
Parrado says they're encouraging parents to get their children screened for undiagnosed heart conditions and to have an AED where children learn and play.
"As long as you're within 1-3 minutes of getting access to the AED, it's going to help you," said Parrado.
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And medical experts say this type of injury is more common in youth baseball, adding it's unusual to occur over the age of 20.
"It happens more commonly in ball sports like baseball when someone takes a ball to the chest, and the reason for that has to do probably with the fact that the ball is a more focal point of impact where the energy is delivered at the spot at the time," said Dr. William Gray, Main Line Health co-director of the Lankenau Heart Institute.
One student-athlete says the sheer number of football-related injuries in the last few years have players concerned about safety, with some leaving the sport entirely.
"I think some people probably because of their parents. Like if my parent were saying like, 'no, you can't play because of head injuries.' But I've been in it for 11 years so I can't just let it go," said Nazye Boggs of Plymouth Meeting.
SEE ALSO: Bills lineman and Temple alum Dion Dawkins speaks about Damar Hamlin