Baseball commissioner Bud Selig (search) is ready to talk to Congress about steroids. It's still uncertain whether star players will appear at Thursday's hearing.

Lawyers for Jason Giambi, Frank Thomas and Rafael Palmeiro asked the committee to withdraw subpoenas for their clients, and lawyers for players and the commissioner's office continued to negotiate with committee staff Monday, trying to narrow the scope of questioning.

Former AL MVP Jose Canseco and Curt Schilling are the only players who have said they are willing to appear at the hearing of the Government Reform Committee in Washington. Selig, who initially offered a top aide as a substitute, reversed course Monday and offered to appear.

"I am proud of the progress baseball has made on the subject of steroids and performance-enhancing drugs and look forward to sharing this information with the committee," he said in a statement. "The players stepped up this past January for an even stricter drug policy beginning this season, demonstrating that all of us in baseball are committed to reaching zero tolerance."

Sammy Sosa and Mark McGwire also were subpoenaed last week along with Canseco, whose recent book alleged several top players used steroids. Union head Donald Fehr (search) was summoned, along with baseball executive vice presidents Rob Manfred and Sandy Alderson, and San Diego general manager Kevin Towers.

Canseco has asked for immunity in order to speak more freely. The committee consulted the Justice Department but didn't expect to hear back until Tuesday evening, according to Canseco's lawyer, Robert Saunooke.

Saunooke said players were unsure whether the committee had power to grant immunity from both federal and state prosecution.

"There's a part of me that would like to believe that once immunity is granted by Congress, there's not a state prosecutor who would thumb their nose at this," he said.

In its subpoena last week, the committee asked for 11 types of documents, including current and past drug-testing agreements and policies going back to 1970, test results from 2003 and 2004, past management bargaining proposals and studies, and details of disciplinary action since 1990 related to drug use. It also asked for results of tests since given to players subject to "cause" testing, a group that includes Darryl Strawberry and Dwight Gooden.

Baseball turned over some of the material Monday.

"We gave them roughly 400 pages of documents, substantial compliance with all of the issues they identified in their subpoena relating to our policies and our aggregate numbers," said Stan Brand, a lawyer for the commissioner's office.

Asked what was not turned over, Brand responded: "We presented them with the gross figures, how many people were tested and how many turned out positive and for what. We did not give anything relating to individual tests and results."

Brand said that because of the short time period, baseball could not assure the committee that all relevant information had been submitted.

"Under the circumstances, I think we're pretty confident we got all that they identified," Brand said.

Committee staff spent Monday examining the documents.

"I don't think they have a sense of what's in there," Robert White, a spokesman for committee chairman Tom Davis said.

David McIntosh and Michael Kantor, lawyers for Giambi, Palmeiro and Thomas, sent three letters to the committee. They asked that Giambi be excused until after the prosecution is over with because of his grand jury testimony.

"Giambi became the focus of extremely negative publicity, not only throughout the nation but worldwide," they wrote. "He will have to live with this stigma for the rest of his life."

For Palmeiro, they said "to require that he come to answer baseless charges is unfair." And for Thomas, they said traveling to Washington "could have adverse circulatory effects that could substantially impede Mr. Thomas's recovery" from ankle surgery.

Davis, a Virginia Republican, has threatened to cite any subpoenaed witness who doesn't appear for contempt of Congress. He also has said one of the seven players summoned might be excused, most likely Giambi, who testified in 2003 before a federal grand jury investigating illegal steroid distribution.

A Yankees official, speaking on condition of anonymity, said it was increasingly likely that Giambi will be excused. However, the subpoena cannot be formally withdrawn until the committee hears back from the Justice Department.