MINNEAPOLIS -- When the NFL suspended Adrian Peterson for the rest of the 2014 season on Nov. 18, commissioner Roger Goodell directed the Minnesota Vikings running back to meet with a league-assigned psychiatrist to design a counseling and therapy program.

In a brief it filed in federal court Monday, the NFL Players Association argued that Goodell did not have the power to attach such terms to Peterson's suspension.

The NFL Players Association is arguing that Roger Goodell does not have the authority to mandate that Adrian Peterson meet with a league-assigned psychiatrist. Hannah Foslien/Getty Images

The union, which is suing the NFL on Peterson's behalf in U.S. District Court, said the terms of Peterson's suspension violate the limits of Goodell's power under the collective bargaining agreement. According to the NFLPA's interpretation of the CBA, the commissioner is allowed only to fine, suspend or terminate the contracts of players and does not have the power to administer additional forms of discipline.

"The collectively-bargained NFL Player Contract could not be clearer in expressly limiting the Commissioner's disciplinary authority 'to fine Player[s] in a reasonable amount, to suspend Player[s] for a certain period or indefinitely; and/or to terminate th[eir] contract[s],'" the NFLPA argued in a 16-page brief. "The NFL does not deny that the Commissioner's imposed counseling requirement is neither a fine, suspension, or contract termination, nor would there be any other 'plausible' interpretation of this CBA provision permitting such a requirement.

"Instead, the NFL -- like the [suspension] itself -- entirely ignores the Player Contract's CBA disciplinary limitation. As the NFL highlights, Arbitrator [Harold] Henderson sustained the counseling requirement of Mr. Peterson's discipline not on the basis of any provision in the CBA, but by relying upon Commissioner Goodell's unilaterally promulgated Personal Conduct Policies."

Goodell ordered Peterson to meet with Dr. April Kuchuk, a New York University instructor in the department of psychiatry and a forensic consultant to the New York City district attorney's office and district courts, by Dec. 1. After Henderson upheld Peterson's suspension on Dec. 12, however, Peterson told ESPN he was wary of participating in the NFL's program and was aware he could run the risk of delaying his reinstatement by not doing so.

"To this point, I feel like any type of process with the NFL is not the way to go," he said. "It's a business; the outcome is going to be in their favor no matter what. Did they appoint Harold Henderson to Ray Rice's case? No. They knew the situation and the facts about that case and what was going to come out. They clearly wanted to get one that would rule in their favor."

Peterson had met with Dr. Cynthia Winston -- a psychology professor at Howard University -- after he was indicted Sept. 12 for recklessly disciplining his 4-year-old son with a switch in the spring. The running back told ESPN he had provided extensive information about his meetings with Winston to the league "and everyone else who's involved and has an interest in what I've done to better myself." Peterson said he apologized to his son immediately after seeing the wounds he inflicted, spoke of plans to start a nonprofit organization to fight child abuse and balked at Goodell's contention he had "shown no remorse."

The league, however, urged Peterson last month to begin counseling and treatment with Kuchuk, according to ESPN NFL Insider Chris Mortensen. Under the terms of his suspension, Peterson is not eligible for reinstatement until April 15. The NFLPA is suing the league to have Peterson reinstated as soon as possible. Judge David Doty is scheduled to hear 30-minute arguments from the union and the league in Minneapolis on Feb. 6.

Neither the NFL nor the NFLPA responded to requests for comment on whether Peterson had met with Kuchuk.