The explosive legal case against Vikings star Adrian Peterson was laid out Saturday in Texas, making it clear that the running back will have to convince a jury that whipping his son was "reasonable discipline."

The outline of the case — coming as the National Football League, the Vikings and Minnesota still were reeling from the news — left it unclear when or whether Peterson would play again, and it ignited an intense national debate among fans and parents about the appropriateness and limits of corporal punishment.

Phil Grant, a Montgomery County (Texas) assistant district attorney, said that a single grand jury had considered the case and decided that Peterson's treatment of his son was "not reasonable.''

"Obviously, parents are entitled to discipline their children as they see fit, except for when that discipline exceeds what the community would say is reasonable," Grant said. "[But] the mental state that's reflected in the indictment is that he did so with criminal negligence, or recklessly."

Grant, speaking at a short news conference, said Peterson might not face trial until next year. If convicted, the Vikings star could face up to two years in a Texas jail and a $10,000 fine. The single-page indictment, handed out at Grant's briefing, charged Peterson with one count of injury to a child.

Peterson's first court date has not been set.

For its part, the NFL had little to say about the case.

NFL spokesman Brian McCarthy said the league was reviewing Peterson's case to check for violations of its personal conduct policy. The policy would seem to give the NFL wide latitude to act — it says that criminal activity "is clearly outside the scope of permissible conduct," and that discipline also can be imposed for "conduct that imposes inherent danger to the safety and well being" of another individual.

The Peterson case comes at the end of a week in which the NFL, and embattled Commissioner Roger Goodell, were the targets of blistering criticism for their initial handling of the domestic-abuse case involving Baltimore star Ray Rice.

The league gave no indication how soon it could act on Peterson's case.

The Vikings star was back in Minnesota on Saturday after taking a late-night round-trip charter to Houston, where he was booked and then released on $15,000 bond. He is not expected to attend Sunday's Vikings home opener against New England.

Blow to star, team

Regardless of the eventual outcome of the criminal case, the charges are a major setback to Peterson and the Vikings.

Long the face of the team, Peterson's photo is prominently displayed at the construction site for the Vikings' new $1 billion stadium in downtown Minneapolis. And his case is a reminder that Vikings fans have endured too many off-field criminal charges and embarrassments by team members in recent years.

The Vikings have had more players arrested — 44 — since 2000 than any other NFL team.

Nike, the multibillion-dollar sporting apparel company that pays Peterson for endorsements, said Saturday it was continuing "to closely monitor the situation."

For some, including former Gov. Arne Carlson, a vocal critic of state financing for the Vikings stadium, Peterson's arrest was more evidence that pro sports — and the money and culture it has created — are out of control.

"We have a society that dearly loves its football — almost at any cost — and therein lies a danger. We're addicted," he said. He said the "tipping point" would only come "when you and I as fans, and as supporters, point to ourselves and say we're part of the problem."

Peterson is set to make $11.75 million this year and will receive another $2.4 million as part of an overall $12 million signing bonus he got as part of a seven-year, $96 million contract — $36 million of it guaranteed — signed in 2011.

Surprise charge?

Grant, the Texas prosecutor, flatly denied widespread media reports Friday that a Texas grand jury last week initially had decided not to indict Peterson.

"It was not shopped around to multiple grand juries," he said.

But the indictment seemed to catch by surprise Peterson's lawyer, Rusty Hardin, who recently left the country on vacation.

Peterson's cooperation with police, and his lawyer's statements saying that the running back was simply treating his child the same way Peterson himself was disciplined at a young age, seemed to suggest an emerging legal defense. Hardin didn't dispute reports indicating that Peterson had whipped his son with a "switch," a tree branch stripped of its leaves.

Michael McCann, the founding director of the New Hampshire-based Sports and Entertainment Law Institute, said Texas is generally more permissive than other states when it comes to spanking or striking children for disciplinary reasons. But he quickly added that the child's age — Peterson's son is 4 — and the severity of the boy's welts pose problems for Peterson in Texas, too.

McCann also said that the episode that allegedly led to the whipping, a scuffle between two small children over a video game, also would be in play in court. Prosecutors, he said, are likely to argue that "a child could not have known at age 4" that fighting over a video game could lead to such a severe whipping.

"This is a 4-year-old boy who got into an argument over a video game," said McCann. "His age is a key factor."

Challenge for defense

Photos of the boy's injuries and a media account quoting from a police report that Peterson stuffed the boy's mouth with leaves during the whipping also could hurt Peterson's defense, McCann said.

"[I've] never heard of anything like that," he said.

Grant did not dispute or confirm those accounts Saturday. He said Texas officials would instead pursue and prosecute those who leaked documents to the media Friday.

In Minnesota, there was no new information about how the case against Peterson was triggered. Texas law enforcement officials said they had initially been alerted of the case by police in Minnesota, and that the child's mother in Minnesota had brought him to a doctor after he returned from visiting Peterson in Texas.

Under state law, a doctor in Minnesota has 24 hours to make a verbal report if they suspect that a child has been neglected or abused. A written report then must be submitted in three days.

Hennepin County Attorney Mike Freeman, while stressing that his office was not involved in Peterson's criminal case, said that child-protection officials hypothetically would look at all options in an abuse case, including possibly a no-contact order against the parent. "The more serious the injury, the more involved the law enforcement and the child-protection workers are," he said.

Future questioned

Peterson's future as a Viking, this season or beyond, also remained in doubt Saturday.

McCann said that Peterson might be unlikely to plead guilty to a lesser offense because doing so, while perhaps quickly putting the case behind him, then would subject him to NFL discipline.

Joe Friedberg, a prominent criminal defense lawyer in Minneapolis, said it bodes well for Peterson that he was charged with reckless or negligent conduct rather than with intentional harm. Crimes committed with intent carry harsher penalties, he said.

Friedberg doubts that Peterson has played his last game in the NFL but questioned whether he could play again in Minnesota. "If he comes out and plays for the Vikings, you're going to have people burning their jerseys outside the stadium," Friedberg said.

New York lawyer Peter Ginsberg said that Peterson can come back. He represented former Vikings Kevin and Pat Williams when they fought their suspensions for taking StarCaps, an over-the-counter supplement found to contain a banned supplement. He also represented NFL quarterback Michael Vick in his bankruptcy proceedings after he went to federal prison for dogfighting. Vick returned to play again in the league.

"I don't believe his career is over," Ginsberg said of Peterson. "People make mistakes, make amends and come back bigger, better, stronger."

But Peterson's legal troubles come at a particularly bad time, he said. Peterson is "clearly subject to being disciplined" because he has acknowledged the whipping. Meanwhile the NFL is caught up in ongoing turmoil about how it treats players who are criminally charged, with Goodell himself a target for critics who see him as too lenient.

"Goodell clearly is under attack," Ginsberg said. "He has significant public relations problems."

Staff writer Master Tesfatsion contributed to this report.