The NFL Players Association sent a letter to the NFL on Friday, calling for the immediate reinstatement of Adrian Peterson per the agreement the sides made for the Minnesota Vikings running back to go on the commissioner's exempt list in September, according to sources.

The agreement to place Peterson on the commissioner's exempt list explicitly states that Peterson would be removed from the list upon resolution of his legal matter, sources said. Peterson pleaded no contest to a misdemeanor last week.

The agreement to place Adrian Peterson on the commissioner's exempt list explicitly states that Peterson would be removed from the list upon resolution of his legal matter, sources said. Peterson plead no contest to a misdemeanor last week. AP Photo/Pat Sullivan

If the NFL declines to comply with the agreement, the NFLPA can then file an expedited non-injury grievance to have Peterson reinstated immediately.

The NFL wants: Peterson to submit all evidence from his court case; independent experts to review those documents; independent experts to make a recommendation on discipline; and after that, they want him to meet with commissioner Roger Goodell to discuss what happened to make a disciplinary decision, which could be creating a new precedent for the new personal conduct policy.

In the first sentence of the letter the NFL sent to Peterson, the league specifically refers to the "felony Injury to a Child" charge -- a clear signal that a no-contest plea to misdemeanor assault may have omitted any reference to child abuse but the NFL will not ignore the incident in its review.

Another NFL official said the agreement was for Peterson to be on paid leave until the completion of his legal proceeding, at which time the matter would be reviewed for potential discipline under the personal conduct policy -- that review is what is taking place now. In other words, no discipline would be processed until there was a resolution by the court. Now the NFL is in the process of the disciplinary review and trying to move as quickly as possible.

The NFLPA's call for immediate reinstatement also uses the argument that Peterson's personal conduct review should be no different than any other player case. The union argues that Peterson should be eligible to play immediately until the league is finished with its review under the personal conduct policy and determines whether there is any disciplinary action.

If that means Peterson is disciplined later under the personal conduct policy, that has been accepted and has precedent. Some amount of time served with loss of pay could be a concept that is part of the equation in the end. Until then, the union says Peterson should be able to practice this coming week and play next Sunday against the Bears.

If Peterson is reinstated, sources say the majority of the Vikings' football operations executives, as well as the coaching staff and players, want the running back on the team.