Palmeiro challenged his drug test and won the right to plead his case before the panel. He wasn't the only one of the first seven suspended players to make such a challenge but was the first to receive a hearing.
At the arbitrator's hearing, the player can address the panel, which Palmeiro did in June.
Because of the way the three-person arbitration panel is constructed, only the independent arbitrator makes a ruling.
It can take many weeks for the arbiter to review a case, which is why Palmeiro's suspension was not announced for months after the original test.
Das refused to comment on the case.
Members of Congress and their staffs said yesterday that they intend to request more information about the case from Major League Baseball.
"There's a lot people don't know," said Robert White, a spokesman for Davis. "I think what we're doing now is just gathering facts about the matter."
The committee is considering sending baseball officials a letter or seeking the information in another way.
White said it is too early to comment further. Another aide familiar with the committee's thinking said the panel wants a detailed chronology.
There have been contacts between members of Congress and baseball since Monday's announcement of Palmeiro's suspension, but the committee does not have all the information it wants.
Palmeiro testified before the committee March 17, along with Orioles teammate Sammy Sosa and a handful of other current and former players and baseball executives. Palmeiro pointedly denied using steroids and offered to be an advocate in educating young people about the risks of steroids.
Palmeiro was summoned to testify largely because of a misunderstanding. Committee staff members, looking for cooperative witnesses, had read a Florida newspaper article suggesting that Palmeiro would be happy to appear. It turned out he was anything but. Palmeiro was then subpoenaed.
Since Monday's suspension announcement, several House members have said they want to know whether Palmeiro lied to Congress.
Palmeiro has said that he didn't intentionally used a banned substance and that he told the truth under oath.
Palmeiro's case might give a push to legislation that would place Major League Baseball, the National Football League, the National Basketball Association and the National Hockey League under the disciplinary regime faced by Olympians who use performance-boosting drugs: a two-year suspension for a first violation and a lifetime ban for a second.