(CNN) -- A 2-year-old boy -- who was the son of Minnesota Vikings star Adrian Peterson, his grandfather told a Minnesota newspaper -- died Friday of injuries he suffered after being allegedly abused, police said.
Sioux Falls, South Dakota, police said Joseph Patterson, 27, has been charged with aggravated battery of an infant and aggravated assault. If convicted on the charges, both felonies, Patterson could face up to 40 years in prison and an $80,000 fine.
Patterson called authorities about 5:45 p.m. Wednesday to a report that a 2-year-old was choking in his Sioux Falls apartment, police spokesman Sam Clemens said. Officers arrived to find that the toddler was unresponsive, and he was rushed to a nearby hospital.
Authorities determined that the child had suffered injuries to his head consistent with abuse, according to Clemens. Police said Patterson, whom they described as the boyfriend of the injured child's mother, was the only other person in the residence at the time.
The suspect -- who was given suspended sentences a year ago for simple domestic assault and violation of a domestic abuse bond, both misdemeanors -- was arrested Thursday night, said Lincoln County, South Dakota, State's Attorney Tom Wollman. A judge set his bail at $750,000 cash during his court appearance Friday, according to Clemens.
The 2-year-old, meanwhile, remained in critical condition at a South Dakota hospital on Friday afternoon, the police spokesman said.
His mother is not under investigation, Clemens added.
"This is an absolute tragedy," Wollman said Friday, "and the parents and the extended family are suffering greatly."
Adrian Peterson's father, Nelson Peterson, told the St. Paul Pioneer Press that the injured toddler is his grandson and Adrian's son. Nelson Peterson did not identify the boy by name except to say he is not Adrian Peterson Jr.
The NFL standout himself did not elaborate on what happened when addressing reporters Friday, though he did acknowledge that he was dealing with "a private matter," adding that he still plans to play in Sunday's game against the Carolina Panthers.
"I will ask you all to please just respect my privacy," Peterson said.