Updated

Croatian tennis player Marin Cilic has received a nine-month suspension for a doping violation, the International Tennis Federation announced Monday.

Cilic, ranked No. 24 in the world, was found to have inadvertently ingested the substance, a prohibited stimulant, as a result of taking glucose tablets.

His suspension is retroactive to May 1, the date he provided the urine sample at the BMW Open in Munich, Germany. The suspension ends Jan. 31 at midnight.

Cilic, 24, said the banned stimulant, nikethamide, was contained in glucose tablets purchased on his behalf from a pharmacy. In accepting his explanation, the ITF gave him a reduced penalty.

Cilic hasn't played since he withdrew from Wimbledon in June. He's been ranked as high as No. 9 in the world.