World record holder Usain Bolt has criticised the decision to reduce Tyson Gay's doping ban because he co-operated with the US Anti-Doping Agency.
Gay and Bolt's fellow Jamaican sprinter Asafa Powell, both 31, failed drug tests in July 2013.
Bolt said: "It is sending a bad message into the sport that you can do it, but if you co-operate with us we'll reduce the sentence."
Former 100m and 200m world champion Gay could have been banned for up to two years after testing positive for a banned anabolic steroid but received a lighter penalty because of his co-operation.
Powell, who tested positive for the banned stimulant oxilofrine, claimed his ruling was "unfair and unjust", and said a legal supplement he took, Epiphany D1, was contaminated.
He appealed to the Court of Arbitration for Sport and his ban was subsequently reduced to six months.
Six-time Olympic champion Bolt does not agree that the athletics world governing body, the IAAF, should have accepted Gay's reduced ban.
"I don't think that's the right way to go because you are pretty much telling people that this is a way out, it's a way of beating the system," he said.
The IAAF said in a statement: "After careful review of the full file provided by Usada, the IAAF has decided that the one-year sanction applied in the case of Tyson Gay was appropriate under the circumstances and in accordance with IAAF Rules."
Both Gay and Powell have now returned to action.