A federal judge in Minnesota on Monday dismissed the NFL Players Association’s collusion complaint against the league that accused teams of operating with a secret salary cap in 2010.

U.S. District Court Judge David S. Doty ruled that the players’ union had agreed in 2011 not to bring such a collusion complaint against the league.

Doty wrote in his ruling that “the NFLPA released the claims it attempts to assert in the underlying action.”

The union filed the complaint in May, charging the league and teams with conspiring improperly to restrict players’ salaries during the 2010 season, during which there was no salary cap. The union alleged that the league operated with a secret salary cap of $123 million per team during the uncapped year.

The union estimated at the time that the secret cap cost players $1 billion or more, which could have resulted in total damages — after being multiplied under provisions in the collective bargaining agreement — of more than $3 billion.

The league denied that collusion had taken place, and maintained that the union had waived its right to bring such a claim under both the CBA and a separate agreement between the two sides.

The union brought its case in the court that oversaw the sport’s previous labor agreement. But Doty sided with the league’s assertion that the union could not bring the case.

The league declined to comment on the dismissal, saying Doty’s ruling spoke for itself.

George Atallah, the union’s assistant executive director of external affairs, said in a written statement: “We pursue the facts and the law to protect players regardless of any outcome. We respect the Judge’s order, but it does not mean that the owners didn’t collude. We will consider any and all other options in light of this decision.”

The union filed its collusion complaint one day after an arbitrator dismissed a case by the Washington Redskins and Dallas Cowboys challenging the salary cap reductions given to them by the league in March with the union’s consent. The Redskins were given a $36 million cap reduction over two years for the manner in which they structured players’ contracts during the uncapped year. The Cowboys were given a $10 million reduction over two years.

The teams denied wrongdoing, but the arbitrator ruled they could not bring such a case challenging the cap reductions because an agreement on the matter between the league and union amounted to a proper amending of the CBA. It was not clear if a successful collusion complaint by the union might have resulted in salary cap space being restored for the Redskins or Cowboys.