Peterson's 2-year-old son died Friday at a hospital in Sioux Falls, S.D., the alleged victim of an assault by his mother's boyfriend.
Lincoln County Attorney Thomas Wollman said the child, whose name was not released at the family's request, had been hospitalized in critical condition at Sanford USD Medical Center with severe head injuries since Wednesday and died after being removed from life support.
A person with knowledge of the situation told the Associated Press the boy was Peterson's son.
Joseph Robert Patterson, 27, who was arrested Wednesday on charges of aggravated assault and battery of an infant, was being held Friday on a $750,000 cash bond.
From the St. Paul Pioneer-Press:
"I should start off by saying I really appreciate all the support that I've been receiving from fans (and) the Vikings organization," Peterson told reporters about an hour after his son's death. "Football is something I will always fall back on," he said. "It gets me through tough times. Just being around the guys in here, that's what I need in my life, guys supporting me, and just being able to go out and play this game I love."