MINNEAPOLIS (AP) - The latest dispute between the NFL Players Association and the NFL over the league's personal conduct policy was aired Friday in federal court, as Adrian Peterson listened to arguments about his suspension that the union is trying to have overturned.

''I felt like I got a fair hearing, for once,'' the Minnesota Vikings running back said to reporters on his way out.

It was more criticism of the disciplinary process that Peterson and the union have derided as arbitrary and unfair since punishment was levied by the NFL after the running back was charged in a child abuse case involving his son. He resolved the case with a plea bargain last year.

Peterson did not speak at the hour-long hearing in front of U.S. District Judge David Doty, who has overseen much of the league's labor matters over the past three decades. Doty took under advisement the NFLPA's petition to nullify the decision by arbitrator Harold Henderson to reject Peterson's appeal of the suspension that is in effect through at least April 15.

Doty did not provide a timetable for his decision.

''I always like good arguments. They make my job harder, but it's always good,'' Doty told the attorneys in attendance.

The basis of the NFLPA's argument is that the enhanced six-game punishment for players involved with domestic violence, announced in August and finalized in December, was unfairly and retroactively applied to Peterson. The injuries to his 4-year-old son occurred in May.

Peterson and the union would prefer a ruling before March 10, when the league's free agency and trading period starts. If the Vikings decide not to bring Peterson back for the 2015 season at his scheduled $12.75 million salary, the process of trading or releasing him or redoing his contract will be complicated by the expiration of the punishment put in place by Commissioner Roger Goodell.

Peterson, for his part, said he wants to return to the Vikings.

''Of course,'' was his answer to that question, smiling as he turned to walk with his wife and agent toward their waiting ride.

About a half-dozen fans with various Vikings clothing, one holding a sign that said, ''Come Back AP,'' shouted their support for the 2012 NFL Most Valuable Player.

''It's good to be back in Minnesota,'' Peterson said.

NFLPA attorney Jeffrey Kessler accused Henderson, a former league executive, of being biased and straying from the collective bargaining agreement in his ruling on the appeal with ''his own brand of industrial justice.''

Another point Kessler made to Doty was that the NFL did not have the right to mandate Peterson participate in the league's assigned counseling per the terms of the punishment that Goodell laid out. Peterson and the NFLPA have said he's seeing a psychologist they picked, to discuss parenting and more appropriate methods of disciplining his children.

''The CBA doesn't give the NFL that authority,'' Kessler said.

Peterson was on a special exempt list, essentially paid leave, while the child abuse case played out in a Texas county court. Soon after the plea deal was reached, the league announced the six-game suspension to cover the remainder of the season. But Kessler argued that the exempt list served as ''pre-discipline discipline'' that Goodell did not have the right to impose.

''Because of public pressure, because of the world, the Commissioner decided to make up a new rule for Mr. Peterson,'' Kessler said.

The NFL's primary response to the claims is that the collective bargaining agreement holds power over the dispute, not the court. Judges rarely overrule arbitration decisions.

Dan Nash, a lawyer for the league, told Doty that Kessler was simply trying to ''re-litigate'' the merits of Peterson's appeal that were already rejected by Henderson.

''We're here on the review of the arbitration award. We're not here for other labor grievances they might have,'' Nash said, often looking to his right in Peterson's direction when he mentioned the player's name.

Nash called the retroactivity argument ''a red herring'' and said proving ''evident partiality'' by Henderson was impossible.

At one point, Doty pressed Nash about league executive Troy Vincent's conversation with Peterson while the disciplinary process was unfolding.

''Don't my lying eyes tell me that Mr. Vincent told Mr. Peterson that he was going to get two games?'' Doty asked.

The union's claim is that Vincent told Peterson he'd only receive a two-game suspension under the old policy. But Vincent testified to Henderson during the appeal hearing that he did not make that guarantee. Nash argued that, even if Vincent's promise were true, it was irrelevant because of a lack of evidence that Peterson acted on that advice.

Kessler used his brief rebuttal time to compare Nash to a read option quarterback, running ''misdirection'' plays with the facts. He also alluded to Doty's work in fostering labor peace between the sides for years and years until the 2011 lockout.

''You can be the person to bring it about again,'' Kessler said, ''and we hope you will.''