Minnesota Vikings defensive tackles Kevin and Pat Williams, who were among six players suspended four games by the NFL for testing positive for a diuretic, said they used the banned substance because they had $400,000 in incentive bonuses in their contracts if they met, or were below, a specific weight during several weigh-ins throughout the year.
The Minneapolis Star Tribune reported the story in Wednesday's editions. The newspaper obtained details from a Dec. 2 letter sent by the NFL to the Williamses' lawyer, which was part of the filings in the the players' suit against the league to nullify their suspensions for violating its anti-doping policy.
The two Vikings tested positive for Bumetanide, which can be used for rapid weight loss or as a masking agent for steroids. They hoped to avoid suspensions because the product they used, StarCaps, did not list Bumetanide as an ingredient.
The NFL Players Association filed an appeal on the players' behalf, but the league denied the appeal, saying it issued a warning about the product in 2006.
According to the Star Tribune, the letter states that both Williamses are subject to receive bonuses if they met or were below a specific weight 11 times during the year -- eight during the season, three in the offseason.
However, the letter specified that the players "would not engage in any 'last-minute weight reduction techniques,' which included 'use of diuretics,'" the Star Tribune reported.
Pat and Kevin Williams, who are not related, have been active in Minnesota's lineup because a federal judge has blocked the suspensions. The NFL wants an appeals court to reconsider the order, according to court documents filed Monday in U.S. District Court in Minnesota.
The Vikings lead the NFC North with a 9-6 record and can win the division with a victory over the New York Giants in Sunday's regular-season finale.
Information from The Associated Press was used in this report.