New York, NY (SportsNetwork.com) - Minnesota Vikings running back Adrian Peterson has been suspended for at least the remainder of the 2014 season for violating the NFL's personal conduct policy.

The suspension, without pay, stems from the abusive discipline Peterson inflicted on his 4-year-old son last May. He was charged with reckless or negligent injury to a child in Texas earlier this year, then pled no contest to a lesser charge on Nov. 4 and avoided jail time.

Peterson was placed on probation while receiving a $4,000 fine and an order to perform 80 hours of community service.

The NFL said Peterson will not be considered for reinstatement before April 15.

NFL commissioner Roger Goodell notified Peterson of the suspension in a letter on Tuesday and said reinstatement will be contingent upon "the results of the counseling and treatment program set forth in this decision.

"We are prepared to put in place a program that can help you to succeed, but no program can succeed without your genuine and continuing engagement. You must commit yourself to your counseling and rehabilitative effort, properly care for your children, and have no further violations of law or league policy."

The NFL Players Association said it will appeal the penalty.

"The NFLPA will appeal this suspension and will demand that a neutral arbitrator oversee the appeal," the union said in a statement.

After playing in the Vikings' season opener, Peterson was indicted by a grand jury in Montgomery County, Texas, on Sept. 11 on accusations he used a wooden tree branch to strike his son as a disciplinary measure. The Vikings placed him on the exempt list shortly afterward and temporarily activated him following the team's Week 2 game against New England, but quickly reversed course after a wave of negative backlash from sponsors, fans and Minnesota governor Mark Dayton.

Peterson was then placed on the commissioner's exempt list and was being paid during that time.

After the case was adjudicated earlier this month, Peterson and the union asked for an instant reinstatement. The NFL rejected the motion and soon after began its review under the personal conduct policy.

The league's personal conduct policy was modified in late August after the Ray Rice domestic abuse incident, establishing a base discipline of a six-game suspension for certain offenses. However, it also allowed for longer penalties for aggravated circumstances, including the use of a weapon or the abuse of children and pregnant women.

Goodell's letter to Peterson outlined the severe issues surrounding the case.

"First, the injury was inflicted on a child who was only four years old," Goodell wrote. "The difference in size and strength between you and the child is significant, and your actions clearly caused physical injury to the child. 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.

"Second, the repetitive use of a switch in this instance is the functional equivalent of a weapon, particularly in the hands of someone with the strength of an accomplished professional athlete.

"Third, you have shown no meaningful remorse for your conduct. 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. You also said that you felt 'very confident with my actions because I know my intent.' 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."

The NFL's statement Tuesday said Peterson did not attend a scheduled hearing to review the case on Nov. 14. The league then tried to reschedule the meeting for the following day, but again was told by Peterson and the NFLPA that the date was unacceptable.

"The well-being of your children is of paramount concern," Goodell also wrote in his letter to Peterson. "In the absence of speaking to you to understand your current disposition toward child discipline, we cannot be sure that this conduct will not be repeated. Moreover, we are unaware of any effort on your part to acknowledge the seriousness of your conduct and your responsibility to demonstrate a genuine commitment to change.

"In order to assess your progress going forward, I will establish periodic reviews, the first of which will be on or about April 15, 2015. At that time, I will meet with you and your representatives and the NFLPA to review the extent to which you have complied with your program of counseling and therapy and both made and lived up to an affirmative commitment to change such that this conduct will not occur again. A failure to cooperate and follow your plan will result in a lengthier suspension without pay."

The NFLPA, in addition to its decision to appeal the penalty, criticized the commissioner's policy in its statement Tuesday.

"The decision by the NFL to suspend Adrian Peterson is another example of the credibility gap that exists between the agreements they make and the actions they take," the NFLPA's statement read. "Since Adrian's legal matter was adjudicated, the NFL has ignored their obligations and attempted to impose a new and arbitrary disciplinary proceeding.

"The facts are that Adrian has asked for a meeting with Roger Goodell, the discipline imposed is inconsistent and an NFL executive told Adrian that his time on the commissioner's list would be considered as time served.

"We call on the NFL Management Council to show our players and our sponsors leadership by committing to collective bargaining so a fair personal conduct policy can be implemented as quickly as possible."

The Vikings issued a statement after the decision and said they would have no comment.