Canseco announced last month on Twitter that he had been subpoenaed in the case.
Prosecutors have asked the federal grand jury in Washington to decide whether to indict Clemens for lying under oath to Congress in 2008 when the seven-time Cy Young Award winner denied using steroids or human growth hormone.
Canseco has previously claimed he introduced several players to performance-enhancing drugs, but the retired slugger has said he has no knowledge of their use by Clemens, a Katy resident.
