Peter Ginsberg says he filed papers Monday in Hennepin County District Court. He wants Judge Gary Larson to say the NFL can't treat the Williamses differently from other players while the battle over their suspensions continues.
League spokesman Greg Aiello denied that the league is retaliating against the two players.
The Williamses tested positive last summer for a banned drug that can mask the use of steroids. They took a weight-loss supplement that contained a banned diuretic that wasn't listed on the label.
The NFL says it intends to enforce the four-game suspensions at the start of this season.
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