Authorities said a 2-year-old boy died Friday of injuries suffered in an alleged child abuse case in South Dakota, and a person with knowledge of the situation told The Associated Press the boy was Peterson's son.
ESPN is also reporting that Peterson's son has died.
Lincoln County State's Attorney Tom Wollman confirmed the death of the child, who had been in critical condition in a hospital with severe head injuries since Wednesday. The boy died at 11:43 a.m. at Sanford USD Medical Center in Sioux Falls after being removed from life support, Wollman said.
Wollman said he'll review police and medical reports before making further decisions about criminal charges, possibly by early next week. Joseph Patterson, 27, was charged with aggravated assault and aggravated battery in the child's death. He had a court appearance Friday and was ordered held on $750,000 cash bond.
Peterson declined to talk about the case after practice Friday, and prosecutors and police in South Dakota declined to confirm the boy was his son. However, a person with knowledge of the situation confirmed the connection to the AP on condition of anonymity because Peterson had requested privacy.
Speaking to reporters about an hour after the time of death, Peterson said he was certain he'll play Sunday against Carolina.
He smiled politely and spoke softly while taking questions at his locker.
"I'll be ready to roll, focused," Peterson said. "I will be playing Sunday, without a doubt."
Peterson is second in the NFL with 421 yards rushing and first in the league with five touchdowns. He came back from reconstructive knee surgery to rush for 2,097 yards and win the league MVP award last season.
"Football is something I will always fall back on," Peterson 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. ... Things that I go through, I've said a thousand times, it helps me play this game to a different level. I'm able to kind of release a lot of my stress through this sport, so that's what I plan on doing."
Later Friday, after news of the boy's death spread, Peterson thanked his family, fans and even fans of other NFL teams for their support.
He tweeted: "The NFL is a fraternity of brothers and I am thankful for the tweets, phone calls and text messages from my fellow players."
Dozens of current and former professional athletes wished Peterson well on Twitter, expressing support, offering prayers and voicing disgust about the alleged abuse.
"Sick for my friend. Strong guy but this one will bring the strongest down," tweeted NBA star LeBron James.
The Panthers, this week's opponent, were sympathetic.
"It's absolutely terrible. Our thoughts and prayers go out to him and his family, and hopefully things work out," coach Ron Rivera said.
Vikings coach Leslie Frazier said he thought Peterson practiced as well as he could Friday considering the circumstance.
"He seems like he was into it, engaged in what he had to get done," Frazier said. "Obviously, tough. He's human. But he was into it mentally, best as he could be."
Fellow running back Toby Gerhart said: "It's hard for any man to admit that he's hurting or he needs help or anything like that. For us to be around him and tell him we've got his back, if there's anything he needs that we're there for him, I think that goes a long way."
AP Sports Writers Jon Krawczynski in Minneapolis and Steve Reed in Charlotte, N.C., and Associated Press writer Carson Walker in Sioux Falls, S.D., contributed to this report.