French tennis player Anthony Dupuis has been banned for 10 weeks after failing to provide a certificate for a drug used to treat asthma.
Dupuis' only ATP title so far came in Milan in 2004
The 33-year-old tested positive for salbutamol at the Tunis Challenger event last May.
He said he took it for medical reasons but did not have an exemption document.
An independent tribunal found that there had been no intent to enhance performance but that the infringement still constituted a doping offence.
An International Tennis Federation statement said: "The player was found to be at fault for failing to take personal responsibility for ensuring that he had a valid Therapeutic Use Exemption to cover the use of the salbutamol."
It also ruled that Dupuis must forfeit the prize money and ranking points earned in Tunis and at subsequent events up to and including the US Open ($30,540).
World number 166 Dupuis, who has three weeks to appeal against the decision, will be eligible to return to competition on 11 November.