This is no longer about deflated footballs.

Tom Brady signaled in his appeal of his "Deflategate" suspension that he will put NFL Commissioner Roger Goodell's credibility on trial, further inflating the stakes in what started as a silly little scandal about the air pressure in footballs.

The expected federal court case - and, to borrow a phrase, it's more probable than not that's just where it's headed - could define or limit the powers of the commissioner long after the Super Bowl MVP returns to the field.

"I think this is much bigger than a four-game suspension for Tom Brady," said Gabe Feldman, a Tulane Law School professor and the director of the Sports Law Program there. "This is part of that continuing battle for the role of the commissioner in disciplinary matters.

"This is a decades-old principal, that the office of the commissioner was created in part to protect the game and to determine what's in the best interest of the league. This is why (the league) bargained for this back in 2011 - that the commissioner is in the best position to determine that."

A four-time Super Bowl champion and the face of the most successful NFL franchise of this century, Brady was suspended four games after a league investigation found he was "at least generally aware" of a scheme to illegally deflate footballs used in the AFC title game. NFL executive vice president Troy Vincent also fined the New England Patriots $1 million and took away two draft picks.

Brady has denied any impropriety, and the NFL Players Association appealed the suspension this week in a three-page letter that demanded Goodell recuse himself as the hearing officer. Loading the letter with references to NFL decisions that were overturned or otherwise botched, union lawyers laid the groundwork for a court case that would take the decision out of his hands.

"They clearly are teeing up some of the issues that they would be following up on appeal," Paul Kelly, the former executive director of the NHL players union, said in an interview with The Associated Press. (AP)

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