The NFL Players Association filed a lawsuit Thursday to block five of the six player suspensions for violating the league's anti-doping policy.

The suit filed in federal court here is on behalf of Kevin Williams and Pat Williams of the Minnesota Vikings, and Charles Grant, Deuce McAllister and Will Smith of the New Orleans Saints.

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The five players were suspended for four games for testing positive for the banned diuretic bumetanide, which can be used as a masking agent for steroids. The drug was in a dietary supplement, StarCaps, that did not list the diuretic as an ingredient.

The suit does not include Houston Texans long snapper Bryan Pittman. David Cornwell, Pittman's lawyer, told the AP that his client isn't included because his circumstances "differ substantially from the men who used StarCaps."

In the lawsuit, the NFLPA alleges both the NFL-appointed doctor and the NFL lawyer who administer the league's steroids policy knew the supplement contained the banned drug but never advised the players. It alleges they breached their duty to the players and endangered their physical well-being.

"It's just common sense that someone shouldn't be punished in those circumstances," David Feher, a lawyer for the union, told The Associated Press.

The union has asked for a hearing Friday for a preliminary injunction so the five players can play this weekend. Feher said the hearing hadn't been scheduled as of Thursday morning, and that it wasn't immediately clear which judge would handle it.

Cornwell said he reviewed Pittman's case with the NFLPA, the player and his agent, Kevin Gold.

"While we remain disappointed in the result, we concluded that, under the circumstances, the chances of a successful challenge were not favorable," Cornwell said.

The NFL has said it sent two notifications about StarCaps on Dec. 19, 2006 — one to NFL club presidents, general managers and head athletic trainers and the second to NFLPA executive Stacy Robinson, who oversees the steroid policy for the union. That letter, according to the league, advised that StarCaps had been added to the list of prohibited dietary supplement companies.

In issuing the suspensions, the league reiterated the section of its policy that reads:

"You and you alone are responsible for what goes into your body. Claiming that you used only legally available nutritional supplements will not help you in an appeal. ... Even if they are bought over-the-counter from a known establishment, there is currently no way to be sure that they contain the ingredients listed on the packaging or have not been tainted with prohibited substances ...

"If you take these products, you do so AT YOUR OWN RISK! For your own health and success in the league, we strongly encourage you to avoid the use of supplements altogether, or at the very least to be extremely careful about what you choose to take."

Kevin and Pat Williams had already obtained a temporary restraining order blocking their suspensions from Hennepin County District Judge Gary Larson on Wednesday. Thursday's lawsuit would protect all five players.