Damar Hamlin remains in critical condition following his unexpected collapse during Monday Night Football in Cincinnati.
The Buffalo Bills Safety was given CPR for over 10 minutes following a hit that knocked him to the ground.
Hamlin was rushed to the hospital in Cincinnati and the game was canceled.
"I want to pray for him and his family because I can only imagine as younger guy that this probably came out of left field for his team, his family, his loved ones," said Abel Contreras, a San Luis Obispo resident.
"Definitely pray for his family and the player," said Mike Gomez, a San Luis Obispo visitor.
The hit to the chest was ultimately what caused Hamlin to collapse during the game.
"Probably in this case, it was Commotio Cordis, which is cardiac arrest that arises from blunt trauma to the chest," said French Hospital Non-Invasive Cardiologist Dr. Lorianna Fletcher. "It's very rare."
The reaction from the players was shock at the scene that unfolded before them.
"Across the board with professional sports in the last few months, people have had heart conditions and strokes and things like that," said Contreras. "It's just sad."
"It was a clean hit," said Gomez. "It wasn't an intentional way of targeting or helmet-to-helmet, it was nothing like that."
"It's shocking and it's happened recently with Eriksen in the European Cup, the soccer player, and the basketball players that have succumbed to sudden cardiac arrest in the past," said Fletcher.
The hit itself is believed to be the cause of the attack.
"You receive a certain amount of blunt energy to a certain area of the chest at a critical time in the heart's cardiac cycle, where the electricity is repolarization," said Fletcher. "The actual timing that the heart is most vulnerable is very short on the order of 40 milliseconds."
The response with paramedics and an ambulance on the field was followed by CPR given to Hamlin.
"If you receive this of energy from blunt trauma at that critical time when the heart is vulnerable, it can precipitate an abnormal heart rhythm called ventricular fibrillation," said Fletcher. "That's a cardiac arrest."
Medical professionals are encouraging the public to learn CPR in light of the event that took place Monday night.
"If there is an AED available, it's very easy to use," said Fletcher. "It tells you exactly what you need to do. You just need to grab it and get it on the patient and try to get it activate it. You can save somebody's life and you can also save their brain, which is really important."
According to Jordon Rooney, Hamlin's marketing representative, he said that Hamlin has been put to sleep with a breathing tube and tests are being run.
The public has shown their support of Hamlin by donating to his charity focused on raising money for toys.
Click here for a link to Hamlin's GoFundMe page.