Peru midfielder Joel Sanchez has been banned for two years after failing a doping test after a World Cup qualifier against Bolivia in October.
Sanchez, who plays for Lima side Universidad San Martin, had tested positive for the banned stimulant methylhexaneamine. The game, Sanchez's second for Peru, was played at La Paz at 13,000 feet above sea level and ended in a 1-1 draw.
The Peruvian soccer federation (FPF) said that the substance was included in a supplement that had been recommended to Sanchez by a nutritionist.
FPF president Manuel Burga said it was "clearly an accidental situation." Sanchez said he had been taking supplements but had no intention of gaining an unfair advantage.