Adrian Peterson spent most of the 2014 season on paid leave while on the commissioner’s exempt list (AP Photo/Houston Chronicle, Billy Smith II)

An arbitrator ruled that the NFL’s policy of placing players on paid leave via the commissioner’s exempt list with cases pending under the personal conduct policy is valid, according to a person familiar with the decision.

The ruling was made by arbitrator Jonathan Marks in a grievance filed by the NFL Players Association early last year contesting the league’s revised personal conduct policy, according to the person with knowledge of the case, who spoke on the condition of anonymity because neither side immediately released or commented on the decision.

The NFLPA filed the grievance in January 2015, soon after the owners voted to ratify the NFL’s revised conduct policy.

The grievance challenged the league’s ability to place players on the exempt list, on what amounts to paid leave, while awaiting a disciplinary ruling by the league on a possible fine or unpaid suspension under the personal conduct policy. Minnesota Vikings running back Adrian Peterson and defensive end Greg Hardy, then with the Carolina Panthers, spent most of the 2014 season on the exempt list, being paid by their teams not to play.

The ruling comes with the NFL and union continuing to negotiate potential changes to the league’s system of player discipline and commissioner Roger Goodell’s role in it. The union is seeking independent arbitration for players’ appeals of penalties imposed by the league under the personal conduct policy and in cases involving the integrity-of-the-game rules. Currently, Goodell is empowered to resolve such appeals.

The arbitrator’s decision also comes with the Second Circuit Court of Appeals considering the NFL’s appeal of the ruling by a federal judge last year that overturned the four-game DeflateGate suspension of New England Patriots quarterback Tom Brady.

A memo sent from league counsel Jeff Pash to all 32 NFL teams said that Marks’s 54-page decision “upholds the new [personal conduct] Policy in all material respects.”

Pash wrote in the memo, a copy of which was obtained by The Washington Post, that the ruling “recognizes and confirms the broad authority tha‎t the Commissioner has to define and impose discipline for conduct detrimental.”

Pash also wrote that the league “negotiated at length with the union to try to resolve this grievance” at Marks’s urging. The following is a further excerpt from Pash’s memo.

“As part of those negotiations, we offered to make changes in the Personal Conduct Policy that would have benefitted players in ways that the union could not obtain from the Arbitrator. Those proposals included giving suspended players credit for a substantial portion of the time spent on the Exempt List (so-called ‘time served’), refraining from imposing discipline until a player’s underlying criminal case was resolved, and expanding the scope of permitted activities and club contact for suspended players. The union elected to terminate negotiations because we would not agree to fundamentally limit the Commissioner’s authority by using third-party appeal officers in all disciplinary matters. The result is that players have obtained very little from the grievance–certainly much less than was available as part of a negotiated resolution–and the authority of the Commissioner has been reconfirmed and strengthened.”