The 2-year-old son of NFL star Adrian Peterson died Friday in a South Dakota hospital after he was allegedly beaten by a man dating the boy's mother, the Sioux Falls Argus Leader reported.

A release from the Sioux City police department said a toddler died "from injuries sustained during the aggravated assault Wednesday." It said it was witholding the child's name but the Associated Press said a person with knowledge of the situation also had confirmed it was Peterson's son.

The police also said Joseph Robert Patterson had made a court appearance in the case and was being held on $750,000 cash bond.

Patterson, 27, was arrested Thursday night and is charged with aggravated assault and aggravated battery of an infant, TMZ reported. The arrest was made after police and paramedics were called to an apartment at 5:43 p.m. Wednesday and found the 2-year-old victim with injuries "consistent with abuse."

Speaking to reporters about an hour after the time of death -- although it was not immediately clear if he knew about it -- AP reported the Minnesota Vikings running back said he was certain he would play Sunday against Carolina.

"I'll be ready to roll, focused," Peterson said. "I will be playing Sunday, without a doubt."

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."

Earlier Friday, Peterson was on the field for stretching with the Vikings. He left for the locker room briefly during special teams drills, which he doesn't participate in, and returned later.

"This is a private matter and I'm just going to ask you all to respect my privacy, and that's all I'm going to say about the situation," Peterson said after practice Friday.

The Associated Press contributed to this report

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