FOXBOROUGH, Mass. (AP) Tom Brady has added more high-profile legal power to fight his ''Deflategate'' suspension.

The AFL-CIO filed a friend of the court brief on Monday asking the 2nd U.S. Circuit Court of Appeals to reconsider a decision handed down by a three-judge panel in April. Also weighing in: Kenneth Feinberg, who helped divvy up the funds for Sept. 11 and Boston Marathon bombing victims.

In its amicus brief, the labor federation said the three-judge panel of the 2nd Circuit that reinstated Brady's four-game suspension erred in granting Commissioner Roger Goodell the ''highly deferential'' status afforded a neutral arbitrator.

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Instead, the AFL-CIO argued that Goodell ''failed to follow basic procedural fairness'' when he originally suspended Brady for his role in a scheme to use improperly inflated footballs in the 2015 AFC Championship game.

''Even a cursory review of the commissioner's decision makes clear that he acted in the self-serving role of an employer justifying his own disciplinary decision rather than as a neutral arbitrator considering an appeal,'' the AFL-CIO wrote.

Feinberg cited his three decades of experience as an arbitrator and special master and said ''the high-profile nature of this case ... has serious potential to affect public confidence'' in the arbitration process. ''Mr. Feinberg comes before this court not to support the unfettered aggrandizement of arbitral powers for he and his fellow arbitrators - but to caution against it,'' he said.

Goodell ''impermissibly exceeded the scope of his authority,'' Feinberg said in his brief. ''But more troubling, he used the vehicle of arbitration as a mechanism to rewrite the underlying bargain between the parties, to the sole advantage of his organization.

''If this type of bias or capricious notions of industrial justice are upheld, the public should - and will - lose faith in the systems of arbitration and private dispute resolution that have become a parallel component of our justice system.''

Brady was suspended four games and the Patriots were docked $1 million and two draft picks for the scandal that has come to be known as ''Deflategate.'' Goodell rejected Brady's initial appeal, and the Patriots star appealed to the federal courts.

Although a district judge overturned the suspension, a 2nd Circuit panel ruled 2-1 for the league on appeal. Brady asked for a re-hearing from the panel or for a hearing in front of the entire, 13-judge circuit, called ''en banc.''

At issue is whether Goodell, in hearing Brady's appeal, used the information obtained in the hearing to buttress the case for Brady's suspension or as new evidence for a new punishment based on a separate violation of the rules.

Brady added former U.S. Solicitor General Ted Olson to his legal team for the appeals; last week, the Patriots joined Brady in arguing for a new hearing - a rare move by an NFL team opposing its league in court.

On Monday, the AFL-CIO joined the case, saying it has extensive experience working with arbitration provisions like the one in Brady's case. It also argued that it has an interest in any decision that helps define the future limits of arbitration.

Feinberg was involved in setting a price for the Zapruder film of the Kennedy assassination and in determining legal fees in a case involving Nazi-era slave laborers.

But he said that a case involving a four-time Super Bowl champion and American's most popular professional sports league ''is of exceptional importance to arbitrators in light of the issues it raises about the power of arbitrators.''

''Mr. Feinberg acutely understands the real-world importance of fairness to the parties' ability to accept an outcome - whatever it may be,'' he argued. ''Often no sum of money can repair the losses victims and their families suffer. `Justice' rests solely upon receiving fair process.''

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Jimmy Golen covers sports and the law for The Associated Press. You can follow him on Twitter at http://www.twitter.com/jgolen .

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Associated Press writer Larry Neumeister contributed to this story from New York.

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AP NFL website: http://pro32.ap.org and http://twitter.com/AP-NFL