Italy's Filippo Volandri has been suspended for three months after testing positive for a banned stimulant and will miss next week's Australian Open.
"The independent tribunal found a sample provided by Mr Volandri on 13 March 2008 at the ATP Tour event in Indian Wells ... contained salbutamol at a concentration greater than 1,000 ng/ml," the International Tennis Federation (ITF) said in a statement on Friday.
The 27-year-old, ranked 109th in the world, blamed his failed test on an inhaler he takes for asthma.
Volandri said he had a medical exemption certificate to use Ventolin, which contains salbutamol, to treat his condition but was deemed to have exceeded his limit.
"The tribunal accepted Mr Volandri had not taken salbutamol with intent to enhance his sporting performance, rather he had taken salbutamol to treat his asthma," the statement added. "However, it found his ATUE (exemption certificate) only permitted him to use asthma medication in line with generally accepted asthma treatment guidelines, and that the amount of salbutamol he inhaled was not consistent with such use and so could not be said to be proper therapeutic use.
"The tribunal therefore found a doping offence had been committed."
Volandri, ranked 25th in the world in 2007, had been scheduled to play Croatia's Mario Ancic in the first round at Melbourne Park.
His ban will last until April 14 and he will also have to forfeit any prize money and ranking points he earned at the Indian Wells tournament, where he was knocked out in the first round.