Cumberland — MINNEAPOLIS — The attorney for two Minnesota Vikings challenging the NFL’s anti-doping policy opened their closely watched trial Monday by accusing the league of failing to follow state law when it tested them for drugs two years ago and then decided to suspend them.

The attorney, Peter Ginsberg, also said the NFL is at least a partial employer of defensive linemen Kevin Williams and Pat Williams. Just who employs the two players when it comes to drug testing is considered a key issue in their lawsuit against the NFL.

“The NFL controls everything about this league,” Ginsberg told the judge.

NFL attorney Dan Nash countered that the league complied with all Minnesota laws in suspending the Williamses, a decision that was later put on hold pending the legal fight. And Nash argued that the NFL’s drug testing rules are a product of collective bargaining with the players’ union.

“The Vikings don’t control drug testing, but neither does the NFL,” Nash said.

The first day of the trial ended without either player taking the stand and it wasn’t clear whether they would do so during a scheduled half-day of testimony Tuesday. The trial is expected to last about a week.

The players tested positive during training camp in 2008 for the banned substance bumetanide, which can mask the presence of steroids. The players, who are not accused of taking steroids, acknowledged taking the over-the-counter weight loss supplement StarCaps the night before a weigh-in so they could meet their weight targets and earn $400,000 bonuses.

Their attorney said NFL officials knew StarCaps contained bumetanide — even though it was not listed as an ingredient on the label — and did not specifically notify the players or the U.S. Food and Drug Administration. The Williamses, who are not related, contend the NFL is their employer and had to comply with Minnesota law requiring notice of a positive drug test within three business days.

The NFL maintains that it properly administered its anti-drug policy, and Nash disputed that the NFL missed the three-day notice requirement. That claim “is not even close to accurate,” Nash said.

Nash successfully objected to several lines of questioning from Ginsberg, including one that dealt with alleged inconsistencies in now the NFL has run its anti-doping program. Nash argued that the questions had already been settled by a federal judge, and Hennepin County Judge Gary Larson agreed.

The trial is expected to settle a number of labor issues, including the question of who employs the players — the NFL, the Vikings, or both — when it comes to drug testing. A state judge has already said that if the NFL employs the players, even partially, then the league has to follow Minnesota labor law.

NFL spokesman Greg Aiello has called the players’ lawsuit a “state law end-around that can undermine all anti-doping policies in sports.” Other sports leagues, including Major League Baseball, the NBA and the NHL, filed court papers backing the NFL, saying the case could affect their ability to enforce their own rules against steroids and other drugs.

The Williamses played last season while challenging the NFL’s plan to suspend them for four games each. They are seeking unspecified damages.

New Orleans Saints players Charles Grant and Will Smith also tested positive for bumetanide but were allowed to play last season, which ended with the Saints winning the Super Bowl after earlier beating the Vikings in the playoffs.

Also to be decided at trial is whether the NFL violated a state confidentiality law. The media learned about the test results before the Williamses or their attorneys, but the league has said there’s no evidence that it leaked the results.

Ginsberg said the NFL did “absolutely nothing to investigate” the leak of the Williams’ failed tests, and said he knew why. “The NFL knew that the leak came from the NFL,” he said.

Nash dismissed that claim.

“I didn’t hear any evidence that anyone at the NFL unlawfully disclosed the test results,” Nash said.