Commotio cordis (Latin, "agitation of the heart") is an often lethal disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart (the precordial region) at a critical time during the cycle...
My guess is he either ruptured his aorta or he took a hard enough blow to his chest that it disrupted the electrical impulse to his heart and it stopped his heart. Happens in car crashes and it happens in sports. Absolutely terrifying and you feel for his teammates, friends and families.
What a terribly callous comment. How dare you speculate on what caused this. /s
