(SportsNetwork.com) - Minnesota Vikings star running back Adrian Peterson missed practice Thursday for personal reasons.

The website TMZ reported Friday morning that Peterson's 2-year old son is in critical condition in Sioux Falls, South Dakota, after being beaten by a man who is dating the mother of the child.

Joseph Robert Patterson is charged with aggravated assault and aggravated assault on an infant in Lincoln County for reportedly harming a 2-year-old boy who was in his care.

Peterson's father talked to the St. Paul Pioneer Press on Friday.

"We are asking for prayers and for respect for our family as we deal with this tragic situation," Nelson Peterson told the newspaper.

According to the paper, Patterson called 911 shortly before 6 p.m. Wednesday to report a choking. At the hospital, it became clear the injuries were not an accident and were consistent with abuse.

During a briefing Friday morning, Sioux Falls Police Department spokesman Sam Clemens said many people have asked about the identity of the boy's father.

"At this point, we're not going to confirm anything. Who the father is does not come into play in this investigation, so we're not going to be releasing any information as far as that goes," Clemens said.

Peterson reportedly returned to the team facility on Friday.

Peterson, last year's NFL MVP, has carried the ball 92 times for 421 yards and five touchdowns in four games for the Vikings this season.

The Vikings host Carolina on Sunday.