Greg F. Anderson (born February 1966) is an American personal trainer, best known for his work with baseball player Barry Bonds, and links with BALCO.
Soon after, Anderson moved back to California where he spent most of his time at the World Gym, now known as Diesel Fitness, only a few blocks away from BALCO.
On July 5, 2006, Anderson was found in contempt of court by U.S. District Judge William Alsup for refusing to testify before a federal grand jury investigating perjury accusations against San Francisco Giants' player Barry Bonds.
Bonds appeared before a grand jury investigating the BALCO steroids case in December 2003 and is reported to have denied knowingly using performance-enhancing drugs.
[10] On March 22, 2011, Anderson was reincarcerated in the Federal Correctional Institution, Dublin on fresh contempt charges for refusing to testify at Bond's perjury trial.