Williams in positive test

Sprinter and stand-up comedian Bernard Williams is the latest American to be caught up in a doping scandal.

Williams, a showman on the track who performs on stage as "Hollywood Williams", received a warning after testing positive for a metabolite of cannabis at a meeting in Spain in June. However, Williams, a gold medallist at the 2000 Sydney Games, remains eligible to run in Athens.

Even when the Americans choose to compete for other countries, they are still getting in trouble. Greek-American baseballers Derek Nicholson and Andrew James Brack have tested positive for banned substances.