A doping researcher who was part of Lance Armstrong's legal team has been banned from sports activities for four years after testing positive for numerous banned substances at the 2019 USA Masters Track Championships.

According to a statement from the U.S. Anti-Doping Agency (USADA), John Greaves, an associate professor of kinesiology at California State University, Fullerton, accepted the ban. He had tested positive for various metabolites of the anabolic steroid oxandrolone and the antiestrogenic drug clomiphene.

Oxandrolone can be used to build muscle, and clomiphene is usually used to treat female infertility and can raise natural testosterone levels.

Grieves' main research interest is "doping in sport" according to his university career, where he served as co-director of the International Network for Doping Research and edited a book on the subject, Doping in Cycling: Doping in Cycling: Interdisciplinary Perspectives), which he edited.

In 2015, Grieves served as an expert witness for Lance Armstrong in a federal whistleblower fraud lawsuit brought by Armstrong's former US Postal teammate, Floyd Landis. Grieves' evidence related to the pervasive nature of doping in the pro peloton at the time of US Postal's doping program.

"Grieves, 36, was a proponent of the metabolites of oxandrolone, 17α-hydroxymethyl-17β-methyl-18-nor-2-oxa-5α-androst-13-en-3-one and 17β-hydroxymethyl-17α-methyl-18-nor-2-oxa-5α-androst tested positive for 13-13-en-3-one, and clomiphene and its metabolite, 4-hydroxyclomiphene, were the results of urine samples collected during competition at the Masters Track National Championships on August 31, 2019," reads a statement from USADA.

"Greaves has accepted a four-year period of ineligibility beginning August 31, 2019, the date the positive sample was taken. In addition, Greaves was disqualified from any competition results (including forfeiture of medals, points, and prizes) obtained after August 31, 2019."

Greaves will be eligible to return to competition in September 2023.

In April 2018, Lance Armstrong reached a $5 million settlement with the federal government; Armstrong, a Texas native who won two Tour de France races in the early 1990s, remains banned from the sport for life.