On Tuesday, the league made a strikingly different example of him.
Instead of allowing Peterson to return after nine weeks of paid suspension for lashing his 4-year-old son with a tree switch, NFL Commissioner Roger Goodell banned him for at least the rest of the season without pay, in part saying he wasn't remorseful enough for punishing a child that way.
The full-season suspension of one of the league's biggest stars underscores Goodell's commitment to enforcing the personal conduct policy he put in place, especially when it comes to incidents of domestic violence. Earlier this year, Goodell's initial leniency of a two-game suspension in punishing Ray Rice, then a star running back for the Baltimore Ravens, cast the league in an unflattering light and jeopardized the commissioner's job.
The NFL Players Assn., which announced Tuesday it would appeal the Peterson punishment, was strident in its criticism of Goodell's decision, calling it "another example of the credibility gap that exists between the agreements they make and the actions they take."
Peterson had been among the league's most prominent and popular players. In 2012, nine months after suffering the type of knee injury that has ended playing careers, he ran for 2,097 yards, coming within nine yards of breaking Eric Dickerson's single-season rushing record. Without Peterson, the Vikings are off to a 4-6 start.
It isn't often the NFL has banished a superstar for a season or longer. Goodell suspended Michael Vick indefinitely in 2007 for the quarterback's role in a dog-fighting ring. Vick spent 19 months in prison and two months of house arrest before returning to the league in 2009. His suspension was lifted one week after leaving federal custody and he was reinstated by the third game of the season.
In 1963, Paul Hornung of the Green Bay Packers and Alex Karras of the Detroit Lions were suspended indefinitely by then-commissioner Pete Rozelle for betting on games and associating with undesirables. Both players returned for the 1964 season.
Coaches have been suspended too, with New Orleans' Sean Payton banned for the 2012 season for his role in the alleged pay-to-injure bounty scandal.
Gabe Feldman, director of the Tulane University Sports Law Program, said the punishments of Rice, who is now indefinitely suspended, and Peterson send a message about the league's determined stance against domestic violence and child abuse.
"Say what you want about the NFL, but this was not the path of least resistance for the league," Feldman said. "The path of least resistance was to credit Adrian Peterson with full time served and force him to pay a hefty fine, and then allow him back on the field. That would have ended the challenges here, it would have ended the arbitration hearings and potential legal dispute, and the league chose not to go down that path."
While some applauded the zero-tolerance approach to banning Peterson without pay — denying him $4.1 million of his $11.75-million salary — others see it as an overreaction to a series of domestic abuse charges leveled against NFL players, specifically Rice.
"The league is hypersensitive now to public image and to the perception that it didn't respond to Ray Rice aggressively enough," USC law professor Jody Armour said. "So now it's going to err on the side of perhaps over-sanctioning rather than risk under-sanctioning and incurring the public wrath again."
The NFL said Peterson will not be considered for reinstatement before April 15. Also Tuesday, an arbitrator sided with the NFL, saying the league was not required to remove Peterson from the exempt list when his legal issues were done, and the commissioner's office has the say as to when Peterson could come off the list.
"The timing of your potential reinstatement will be based on the results of the counseling and treatment program set forth in this decision," Goodell wrote to Peterson in a letter made public by the league.
Peterson pleaded no contest Nov. 4 in Texas to reduced charges of misdemeanor reckless assault for hitting his son with a tree switch, leaving scratches and welts on the child's body. The deal allowed Peterson to avoid jail time in exchange for probation, a $4,000 fine and 80 hours of community service.
"The difference in size and strength between you and the child is significant, and your actions clearly caused physical injury to the child," Goodell wrote. "While an adult may have a number of options when confronted with abuse — to flee, to fight back, or to seek help from law enforcement — none of those options is realistically available to a 4-year-old child. Further, the injury inflicted on your son includes the emotional and psychological trauma to a young child who suffers criminal physical abuse at the hands of his father."
Child advocate Deanne Tilton Durfee said she was "very encouraged" by the action the NFL took in the Peterson case.
"It reflects appreciation of the harms both physically and psychologically that can come from inflicting pain on a very young and helpless child," said Tilton Durfee, executive director of the Interagency Council on Child Abuse and Neglect. "If these injuries had been inflicted on another adult, then [Peterson] clearly would have been guilty of a crime."
Peterson's punishment stands in stark contrast to the one Goodell initially levied against Rice five months earlier. Rice originally received the two-game suspension before a surveillance video surfaced, showing Rice striking Janay Palmer, now his wife, and knocking her unconscious. Rice was cut by the Ravens and suspended indefinitely by the NFL. So appalling were the images that the league's reputation was severely tarnished, sponsors began to waver, and Goodell's $44-million job dangled in the balance.
It prompted the nation's most successful sports league to focus on domestic violence issues, turning up the pressure on Goodell to act decisively in the case of Peterson, who had agreed to be placed on the newly formed exempt/commissioner's permission list with the belief he not only would be paid but would be reinstated once his legal issues were resolved.
The NFLPA said Peterson was told by an unidentified league executive that being on that list would count as time served toward a suspension. According to NFL spokesman Brian McCarthy, his time on the exempt list was considered.
"There were aggravating circumstances that led to the discipline announced," McCarthy said.
In August, the NFL announced ramped-up penalties for players who commit acts of domestic violence, with first offenses of assault, battery or domestic violence bringing a six-game suspension. Carolina defensive end Greg Hardy, awaiting a jury trial on domestic violence charges, is also on the commissioner's exempt list.
In his letter to Peterson, Goodell said the switch was essentially a weapon.
"When indicted, you acknowledged what you did but said that you would not 'eliminate whooping my kids' and defended your conduct in numerous published text messages to the child's mother," Goodell wrote.
"These comments raise the serious concern that you do not fully appreciate the seriousness of your conduct, or even worse, that you may feel free to engage in similar conduct in the future."
Follow Sam Farmer on Twitter @latimesfarmer