Croatian player Marin Cilic was handed a nine-month suspension by the International Tennis Federation on Monday after testing positive for a banned substance.
The suspension was back-dated to May 1 and will last through Jan. 31, 2014.
Cilic tested positive for nikethamide, a stimulant, at a tournament in Munich last spring. The ITF said it accepted the player's contention that he ingested the substance inadvertently in glucose tablets and was not trying to cheat.
As a result, the ITF gave him a reduced penalty rather than a ban of up to two years.
"Mr. Cilic asserted that the nikethamide, for which he did not hold a valid TUE (Therapeutic Use Exemption), had entered his system through his ingestion of Coramine glucose tablets that had been purchased on his behalf from a pharmacy,'' the ITF said in a statement. "The Independent Tribunal found that Mr Cilic ingested the nikethamide inadvertently as a result of taking the Coramine glucose tablets, and did not intend to enhance his performance in doing so.''