Adrian Peterson lawsuit against NFL filed Monday in Minneapolis

The NFL Players Association has filed a lawsuit against the league on behalf of suspended Minnesota Vikings running back Adrian Peterson.

The NFL Players Association has filed a lawsuit on behalf of suspended Minnesota Vikings running back Adrian Peterson against the NFL in federal court in Minneapolis, MN, on Monday morning, according to a release from the NFLPA.

The NFLPA's intention to file suit was reported by Tom Pelissero of USA TODAY Sports on Sunday evening.

The suit is expected to challenge the impartiality of Harold Henderson, who upheld NFL commissioner Roger Goodell's suspension of Peterson on Friday. Henderson, a former league employee for nearly two decades, called Peterson's domestic abuse case "arguably one of the most egregious cases of domestic violence" under Goodell's nine-year tenure as commissioner.

• McCann: Exploring Peterson's legal options following failed appeal

Peterson was suspended for the season in November after he was indicted on felony charges of reckless or negligent injury to a child in September. He pleaded no contest to misdemeanor reckless assault on Nov. 4 after authorities claimed he hit his 4-year-old son with a switch.

Peterson cannot be reinstated before April 15, 2015.

After Henderson's decision was handed down, the NFLPA responded in a statement:

The NFLPA expected this outcome, given the hearing officer's relationship and financial ties to the NFL. The decision itself ignores the facts, the evidence and the collective bargaining agreement. This decision also represents the NFL's repeated failure to adhere to due process and confirms its inconsistent treatment of players. Our union is considering immediate legal remedies.

At the hearing last week, the union argued that Peterson was punished retroactively under Goodell's changes to the personal conduct policy in August. It also said Peterson was subjected to a "new and obfuscated disciplinary process," according to USA TODAY.

Henderson rejected those claims in his ruling:

I conclude that the player has not demonstrated that the process and procedures surrounding his discipline were not fair and consistent; he was afforded all the protections and rights to which he is entitled, and I find no basis to vacate or reduce the discipline.

Henderson also echoed Goodell's claims in a letter to Peterson that the Vikings star failed to "reflect remorse or appreciation for the seriousness of his actions."

- Mike Fiammetta