MIAMI -- New York Yankees first baseman Jason Giambi is among the players subpoenaed by a federal grand jury investigating a company that prescribes nutritional supplements for elite athletes.

Giambi is among the 40 big-name athletes -- Barry Bonds of the San Francisco Giants and world-class sprinter Kelli White included -- who have been asked to testify in the budding steroid scandal.

Giambi, in Miami for Game 3 of the World Series against the Marlins, said he didn't know much about the investigation into Bay Area Laboratory Co-Operative, or BALCO.

"I really don't know what it's about," Giambi said. "I'm not worried about it. I didn't do anything wrong. As much as has been printed, I don't even know if that's accurate."

He added: "I know BALCO but I really don't know much about it."

Before the second game of the World Series on Sunday, Giambi told the San Francisco Chronicle, "Uh, yeah, I was," when asked if he had been subpoenaed in connection with the BALCO probe.

Giambi said he visited BALCO last fall before going on a tour of Japan with other major leaguers.

"I just asked about some vitamins and supplements and stuff like that," Giambi told the newspaper. "No big deal."

Burlingame (Calif.)-based BALCO, whose clients also include Oakland Raiders linebacker Bill Romanowski and sprinters Marion Jones and Tim Montgomery, was raided last month by agents of the Internal Revenue Service and a San Mateo County narcotics task force.

An attorney for Barry Bonds told the San Francisco Chronicle that Bonds was subpoenaed and will testify Dec. 4. The home of Bonds' personal trainer, Greg Anderson, was raided last month in conjunction with the raid on founder Victor Conte's lab.

"They have verbally told me that Barry is not a target," lawyer Michael Rains said. "I called and invited the prosecuting attorney to sit down with me and possibly even with Barry at some date before his appearance to see if we could hash out what it is they need to know and whether or not Barry has any useful information."

Authorities have refused to discuss the case, and the focus of the grand jury is unclear. Officials with the U.S. Anti-Doping Agency, however, have said that earlier this year, a coach sent them a syringe containing the designer steroid tetrahydrogestrinone, or THG, that the coach said he got from Conte.

Conte has denied being the source of the substance in the syringe.

"In my opinion, this is about jealous competitive coaches and athletes that all have a history of promoting and using performance-enhancing agents being completely hypocritical in their actions," he said.

BALCO analyzes blood and urine samples from athletes, and then prescribes supplements to compensate for deficiencies in vitamins and minerals.

Although many of BALCO's star clients have not commented on the burgeoning case, the agent for U.S. shot put champion Kevin Toth told the AP that Toth had been subpoenaed.

In a statement released by his attorney Sunday, Toth claims he has never heard of THG for which he reportedly tested positive. Toth has had no previous positive tests, his agent John Nubani said.

"While I wish I could tell my side of the story at this time, I cannot do so until this case, if there even is a case, has been decided through the legal system provided by the IAAF [International Associations of Athletics Federations] and USADA [U.S. Anti-Doping Agency]," Toth said in the statement.

White told The Chronicle that she too has been called to the grand jury, but denied having a role in the steroid inquiry. Testimony before the panel is expected to begin this week.

"I really don't have anything to do with that situation," she said. "That's not me."

Conte told the San Jose Mercury News and The Chronicle that seven professional football players and five Major League Baseball players were among those compelled to testify in hearings on the West Coast that are expected to begin this week.

In the June issue of Muscle & Fitness magazine, Bonds enthused about Conte's physical fitness regimen and nutritional advice, saying, "I'm just shocked by what they've been able to do for me."

The doping scandal erupted earlier this week when news broke that three track and field athletes who flunked drug tests had been subpoenaed to testify before a federal grand jury that is investigating what one anti-doping official calls "an international doping conspiracy."

The three athletes were tested at the U.S. Track & Field Nationals in Palo Alto, Calif., in June and one of the athletes was a client of BALCO. The controversial nutritionist boasts of a roster of professional and Olympic sports stars as customers, and one source close to the case said Thursday that "the names I've heard are some of the biggest names in sports."

"I know of no other drug bust that is larger than this involving the number of athletes involved," anti-doping official Terry Madden, director of the U.S Anti-Doping Agency, told The Associated Press on Friday. He refused to reveal the names or genders of the athletes, or to be more specific about how many had tested positive.

On Thursday, Madden identified Conte as the alleged supplier of the previously undetected steroid THG, which was detected in the three athletes.

"What we have uncovered appears to be intentional doping of the worst sort," Madden said during a news conference. He called the case "a conspiracy involving chemists, coaches and certain athletes to defraud their competitors, and the American and world public who pay to attend sporting events."

In September, agents for the Internal Revenue Service raided BALCO, in Burlingame, Calif., carting out boxes of records and raising suspicions that federal agents are interested in its finances. By then, Madden said, they already had been told about USADA's findings. Besides Bonds and White, BALCO's clients include, Bill Romanowksi, and Olympic stars Jones and Montgomery.