Adrian Peterson’s desire to return quickly to the Vikings has ramped up the acrimony between the NFL and the league’s players association.

Peterson on Sunday accused the NFL of lying and adopting a “new process of discipline” in its refusal to reinstate the Vikings star running back from the commissioner’s exempt list.

Peterson has a scheduled hearing by teleconference Monday after the NFL Players Association filed an expedited grievance in an attempt to get him back on the field as soon as possible.

But a league spokesman, Brian McCarthy, said Peterson was scheduled to meet with league officials Friday to discuss punishment after his court case on a child assault charge was settled and that Peterson declined to attend.

Peterson pleaded no contest two weeks ago to a misdemeanor charge of reckless assault in a case involving him disciplining a 4-year-old son with a wooden switch, a case in which he originally was charged with a felony. He missed nine games, and claims that under terms of an agreement he signed Sept. 16 to go on the exempt list, he would be reinstated once the court case was settled.

Asked about Peterson’s possible return after Sunday’s 21-13 loss in Chicago, Vikings coach Mike Zimmer said: “That’s the furthest thing from my mind right now. I need to figure out how we can tackle and get people out on third downs.”

On Sunday, Peterson released a statement through the NFLPA, claiming the pre-discipline hearing wasn’t part of the NFL’s collective bargaining agreement.

The statement read: “The report that I backed out of a meeting with the NFL is just not true. When [Commissioner] Roger Goodell’s office asked that I attend the ‘hearing’ on Friday, I consulted with my union and learned that this ‘hearing’ was something new and inconsistent with the CBA. On Tuesday, Wednesday, and Thursday of this past week, my union sent e-mails, letters, and had conversations with his office on my behalf asking about the nature of the hearing, how it was to occur, who would participate, and its purpose. We repeatedly asked them to respond quickly to my questions because I want to cooperate and get back on the field, but they didn’t respond until late Wednesday evening, and even then they didn’t answer important questions about their proposed ‘hearing.’

“After consulting with the union, I told the NFL that I will attend the standard meeting with the Commissioner prior to possible imposition of discipline, as has been the long-term practice under the CBA, but I wouldn’t participate in a newly created and non-collectively bargained pre-discipline ‘hearing’ that would include outside people I don’t know and who would have roles in the process that the NFL wouldn’t disclose. At this point, I’ve resolved my matter in the criminal court; I’ve worked to make amends for what I’ve done; I’ve missed most of the season, and I stand ready to be candid and forthcoming with Mr. Goodell about what happened. However, I will not allow the NFL to impose a new process of discipline on me, ignore the CBA, ignore the deal they agreed to with me, and behave without fairness or accountability. The process they are pushing is arbitrary, inconsistent, and contrary to what they agreed to do, and for those reasons, I never agreed to the hearing.

“I’m sorry for all of this, but I can’t excuse their refusal to be fair.”

The NFL will judge Peterson under its revamped personal conduct policy, which calls for players involved in domestic violence to be suspended for six games. The new policy was announced by Goodell in August; the injury to Peterson’s son occurred in May. Peterson has been paid while absent from action.

Monday’s grievance hearing will be handled by Shyam Das, an arbiter used by the NFL and NFLPA under the collective bargaining agreement reached in 2011.