Sports agent William ``Tank'' Black sued the NFL Players Association on Tuesday, contending his business has been hurt by a complaint from the union.

The lawsuit was filed in federal court in Washington. Mike Butler, spokesman for Black's company, Professional Management Inc., said only that the suit addresses the disciplinary complaint the union filed against Black last month.

The NFLPA accused Black of making improper contact with former Florida players. The union could revoke Black's license if it finds him guilty of paying players before their eligibility had expired.

``I haven't seen it, but I can tell you this, I would expect it to have no effect on our disciplinary proceedings which are ongoing and require an answer from Mr. Black at the end of the month,'' NFLPA attorney Richard Berthelsen said. ``If this is an answer to our disciplinary complaint, it's an obvious attempt to deflect attention away from his conduct.''

Black and lawyer Leonard Mungo have called a news conference for Wednesday in Orlando, Fla., to discuss the suit.

``I have lost tremendously in a couple of areas,'' Black told The Florida Today. ``I've lost four clients _ and they were top clients _ and, obviously, the funds associated with the clients over the next 10 years.''

One player, Johnny Rutledge, said he accepted $500 payments from Black last year while still enrolled at Florida. Rutledge said he and two other former Gators, Jevon Kearse and Reggie McGrew, have made sworn statements saying they received payments.

Black and Mungo have argued that the NFLPA's disciplinary system violates Black's civil rights, forcing the agent to prove himself innocent after being accused. They have also charged that the NFLPA unlawfully used the powers of the University of Florida police, which is also investigating Black, to further its own search.

Mungo has complained that NFLPA representative Trace Armstrong was present during police questioning of players.

``We're not going to turn down information because it comes from sources outside the NFL. If we did, we're not doing our jobs,'' Berthelsen said.

Berthelsen said the NFLPA has evidence apart from that gleaned during the interview that Armstrong attended.

He also said all agents sign a contract stating they understand union policy.

Black is also working on a reply to the NFLPA complaint.

University police have not filed any charges. They declined comment on the investigation.