Alex Bogomolov Jr has been suspended for one and a half months after testing positive for banned substance salbutamol at the Australian Open.
Bogomolov Jr is ranked a lowly 190th in the world
The International Tennis Federation accepted the American's explanation that he took the drug to treat asthma.
However, an ITF statement read: "The player was found to be at fault for failing to ensure that he had a valid Therapeutic Use Exemption."
Bogomolov, 22, went out in the first round of qualifying in Melbourne.
His suspension will start on 26 September and he must also forfeit prize money and ranking points earned at the Australian Open and events up to and including the Mexico City Challenger which ended on 10 April.
He can return to competition on 10 November.