In "Vindicated," his second book on the performance-enhancing drug scandal in baseball, Canseco wrote that he introduced New York Yankees third baseman Alex Rodriguez to a steroid distributor that he only identified as "Max." Canseco said the supplier later told him that A-Rod had "signed on."
Rodriguez has refused to comment on the allegation, while Canseco has refused to discuss the identity of "Max." When ABC's "Nightline" interviewer Martin Bashir challenged Canseco to identify "Max" or provide other evidence of the account, Canseco responded that "the timing's not right."
Greg S. Emerson, a lawyer for Canseco, said his client intends to answer all questions posed to him by investigators. While he doesn't know exactly what they will ask, he has a feeling that "Max" will be part of the conversation, he told The New York Times.
"Jose intends to speak truthfully with authorities and I cannot comment on the identity of Max, how that may come up or anything else that may be discussed," Emerson said, according to the report.
Despite writing two books about steroid and HGH use and testifying about it before a congressional committee, Canseco has until now never been questioned by federal agents about performance-enhancing drugs, The Times reported.
Canseco is not believed to be a target in the Clemens probe and may choose not to answer certain questions when he is interviewed on Tuesday. That could change if a grand jury is convened in the Clemens case, in which case Canseco could be subpoenaed and compelled to testify under oath and answer all questions under the threat of criminal prosecution.
Canseco is being questioned in the FBI's investigation of whether Clemens testified truthfully to federal agents and before a congressional committee when he said he had never taken steroids or human growth hormone.
Clemens' former trainer, Brian McNamee, told federal investigators and former U.S. Sen. George Mitchell that he injected Clemens with steroids and human growth hormone on several occasions, leading to Clemens being named in Mitchell's report on performance-enhancing drug use in baseball. Clemens has repeatedly denied ever using steroids or HGH.
One of the questions posed to Clemens and McNamee dealt with a pool party at Canseco's house in 1998. McNamee has said Clemens spoke with Canseco at the barbecue and soon after approached the trainer about using performance-enhancing drugs. Clemens said he didn't attend the party, and Canseco corroborated Clemens' story in an affidavit to Congress. But a photograph allegedly shows Clemens in attendance, and IRS agent Jeff Novitzky, who has been the federal government's top steroid investigator, wants to talk to Canseco about the picture.
Another lawyer for Canseco, Robert Saunooke, has said Novitzky has described two photos to him -- one of Clemens and an 11-year-old boy in Canseco's pool and another of Canseco with the same boy. From the description, the undated photos in no way linked Clemens to the specific party in question, Saunooke said.
The Associated Press contributed to this report.