Mankato, Minn. ? The NFL Players Association claims the Minnesota Vikings and Kansas City Chiefs may have engaged in collusion in their negotiations with unsigned first-round draft picks Bryant McKinnie and Ryan Sims.

The union filed a request for an investigation on Monday with the NFL Management Council, ESPN.com first reported Tuesday.

The union claims the teams may have had knowledge of the signing bonus offered to a player picked after Sims and McKinnie which is not permitted and subsequently offered the two players a lower amount.

“If two clubs take the same position (on offers to their players), then one player can’t say, ‘Look, No. 7 signed for this or that amount, so I should get a few bucks more,”‘ Richard Berthelsen, an attorney for the players group, told the Associated Press.

Sims and McKinnie were picked with the sixth and seventh picks, respectively. The No. 8 pick who the union said was offered the larger signing bonus was safety Roy Williams of the Dallas Cowboys.

Berthelsen said a letter to the management council asks for information about any communication between the Chiefs and Vikings regarding negotiations with their top draft picks.

Rob Brzezinski, vice president of football operations for the Vikings, called the accusations “ridiculous” and “baseless.”

Carl Peterson, president and general manager of the Chiefs, also said the claims were baseless. He said Kansas City has never discussed contract talks with any other teams.

“The only conversations that we ever have with other clubs is usually, ‘It’s too bad you can’t get your guy done, we’re struggling also,”‘ he said. “There’s been no discussions.”