USA Today reports that the toddler was the victim of alleged abuse by Joseph Robert Patterson, who was reportedly dating the boy's mother.
Peterson, who is a star player for the Minnesota Vikings, was excused from practice on Thursday to deal with the heartbreaking situation that ended in tragedy.
He spoke to the press just hours before his son died, stating that really appreciated "all the support that I've been receiving from fans, the Vikings organization."
He indicated that he would be playing in Sunday's game against Carolina, but would not talk about the case.
"This is a private matter and I would ask you all to please just respect my privacy and not ask at all about the situation at hand."
NBC reports that Joseph Robert Patterson, 27, was arrested and charged with aggravated assault and aggravated assault on an infant. Sioux Falls police stated that he may face additional charges.
Sioux Falls police spokesman Sam Clemens told USA TODAY Sports that the abuse incident was initially reported to police as a medical emergency.
"As officers and first responders got there, they found child was unresponsive and he was taken to the hospital ... What they ended up finding was that when the injuries happened there was one person with that child, and that person was Joseph Patterson."
Clemens stated that the injuries were "head injuries" and that medical staff at the hospital confirmed that they were not accidental injuries.
Police believe that the child's mother was not home at the time the child was allegedly abused by Patterson.
USA Today reports that Patterson, who recently started a relationship with the mother of Adrian Peterson's baby, has a record of prior domestic abuse with another woman and her child.
In 2012, he pleaded guilty to simple assault after being charged with the abuse of an adult female and juvenile male.
Before the child died, Patterson's bond was set at $750,000 cash. It has been speculated in the media that this bail may be increased or he may be held without bail now that Peterson's son died from his injuries.