The National Football League's labor war continued yesterday when the NFL Management Council filed an antitrust suit in federal court in Minneapolis against the NFL Players Association. In the latest round of a bitter and expensive legal scrimmage, management is upset that the NFLPA continues to act as a union after having decertified itself.

Specifically, management charges the NFLPA of distributing salary information to the agents of rookies, creating what amounts to a salary scale. The suit seeks treble damages and other relief against the NFLPA and individual player agents, who will be named in later filings.

"If the NFLPA isn't a union, then its activities in exchanging salary data and coordinating bargaining with the agents are illegal," said Jack Donlan, executive director of the NFL Management Council. "The agents and the NFLPA can't have it both ways."

Gene Upshaw, executive director of the NFLPA, said he welcomed an examination of his group's work. "What we do is pro-competitive," he said. "Players can't fix wages. They negotiate individually. . . . We know the {teams} share salary information via a computer network and use this shared information to slot players and to fix wages. Professional associations share member compensation information everyday. The NFLPA is no different." . . .

Veteran quarterback Doug Williams remains unsigned five months after being released by the Washington Redskins, but said he still hopes to play in 1990. Williams, 34, said he believes he'll be offered a contract in a few weeks.

"It doesn't bother me not going to camp," he said. "The big thing is staying ready to play and that's a mental thing. The physical part is easier because I've been doing that for a long time. I'll take care of myself. I'd prefer to be signed right now, but it's not something I can control."

Williams has had one tryout, with the Los Angeles Raiders.