NEW ORLEANS (AP) - The NFL Players Association filed a lawsuit against the NFL on behalf of three players suspended in connection with the bounty investigation, calling Commissioner Roger Goodell "incurably and evidently biased."

The lawsuit, filed in federal court in New Orleans on Thursday, said Goodell violated the labor agreement by showing he had determined Will Smith, Anthony Hargrove and Scott Fujita participated in a bounty system before serving as an arbitrator at their hearing.

The NFL said the action is an "improper attempt to litigate" and said there is "no basis for asking a federal court to put its judgment in place of the procedures agreed upon with the NFLPA in collective bargaining."

"These procedures have been in place, and have served the game and players well, for many decades," NFL spokesman Greg Aiello said in an email to The Associated Press.

The lawsuit asks a judge to set aside earlier arbitration rulings and order a new arbitrator to preside over the matter. The suit comes two days after Goodell denied appeals by four players. The other player, Jonathan Vilma, has sued the NFL and Goodell separately.

Vilma's lawsuits include initial defamation claims against Goodell, which the commissioner denied Thursday in an expected motion to dismiss. The motion states that Vilma is barred from making such claims by the dispute resolution process outlined in the NFL's labor agreement, which also includes a provision barring lawsuits by players against the NFL.

Vilma, meanwhile, on Thursday amended his consolidated lawsuits against Goodell and the league, asking a judge to overturn the NFL's suspension and issue a temporary injunction to allow Vilma to keep working while his case is pending.

The Saints linebacker, whose suspension is effective immediately, wants the injunction so he may resume rehabilitating his left knee injury at Saints headquarters.

Vilma is suspended for a season, Hargrove for eight games, Smith four and Fujita three. Vilma and Smith still play for New Orleans, while Hargrove is with Green Bay and Fujita is with Cleveland.

The NFL has said it found that former Saints defensive coordinator Gregg Williams ran a bounty program that paid improper cash bonuses for injuring opponents. Saints had coach Sean Payton has been suspended the entire 2012 season for failing to put a stop to it, while general manager Mickey Loomis has been suspended half a season and assistant head coach Joe Vitt six games.

Williams, now with St. Louis, is suspended indefinitely and, according to the NFL, cooperating with the investigation.

The players, however, have claimed they sought or accepted rewards for injuring opponents. Fujita has said the NFL grossly mischaracterized what was an informal accountability program to reward one another for big plays such as sacks, forced fumbles and interceptions, something players on many teams have taken part in for years.

Several current Saints defensive players who have not been punished, including safety Roman Harper and linebacker Scott Shanle, have publicly defended their current and former teammates, denying that any Saints player sought to do anything more than what they were already paid to do - deliver clean hits as hard as they could.

Some players have also suggested that Goodell's bounty punishments are part of an agenda to make the league look tough on player-safety matters in order to mitigate exposure to lawsuits filed by numerous retired NFL players who claim the league failed to educate them about or prepare them for many of the long-term physical ailments, including brain disease.

"A seminal question for this court is whether the NFL collective bargaining agreement ... granted the commissioner, when serving as an arbitrator, the authority to disregard the essence of the parties' agreement, to conduct proceedings that are fundamentally unfair, and to act with evident bias and without jurisdiction," the lawsuit states. "The answer, under governing case law, is clearly 'no.'"

In the lawsuit, the players, as they have in the past, "categorically" deny participating in any kind of "bounty" program designed to injure fellow players, and the NFLPA adds that it would never defend who did conspire to injure their peers on the field.

"The investigation and arbitration process that the Commissioner's public relations machinery touted as 'thorough and fair' has, in reality, been a sham," the lawsuit stated.

The lawsuit said the NFL violated the labor agreement by refusing to provide the players with access to "critical documents or witnesses, or anything resembling the fairness mandated by the CBA and governing industrial due process law."

The suit also states that the players were subject to arbitration before an arbiter in Goodell, who had "launched a public campaign defending the punishments he intended to arbitrate, rendering him incurably and evidently biased."

The lawsuit also reiterates a claim that the CBA requires many of the "pay-for-performance" conduct outlined in the NFL's bounty investigation to be handled by a system arbitrator and not the commissioner, who has "improperly usurped" control over that process.

The NFL has argued that the bounty matter falls under conduct detrimental to the league, which the commissioner has authority to punish. Two arbitration rulings so far have ruled in the NFL's favor on that matter, but the NFLPA lawsuit says the NFL's handling of the bounty matter amounts to a "rare case" in which the arbitrator's rulings should be set aside.

The union contends the arbitrator, Stephen Burbank, made his decision based on the fact that he saw his jurisdiction covering only improper payments made to players, but not the payments the NFL has said players made into the bounty pool.

"This distinction cannot be justified by the CBA, nor can it override the fact that the NFLPA has never agreed to arbitrate these types of disputes before the Commissioner," the lawsuit said.

Included with the 55-page lawsuit are 400 pages of exhibits, including about 200 pages of evidence that the NFL presented at a June 18 appeal hearing. The lawsuit notes that those documents represent a "sparse" sampling of the 18,000 documents totaling about 50,000 pages that the NFL said it had compiled during the three-year course of its investigation.

Also included is a sworn declaration from Duke Naipohn, a fatigue risk management specialist who was working closely with the Saints defense throughout the 2011 season. Naipohn said he attended most defensive meetings and never saw bounties placed on opposing players or saw Saints players rewarded for injuring opponents.