Former top-10 player Marin Cilic has been suspended nine months for a doping violation.
The International Tennis Federation said Monday that the suspension was back-dated to May 1, so Cilic will be able to return to the circuit Jan. 31.
Cilic tested positive for nikethamide, a stimulant, in Munich.
The ITF says an independent tribunal found that Cilic ingested the stimulant inadvertently while taking glucose tablets "and did not intend to enhance his performance in doing so."
The 24-year-old from Croatia has not played since withdrawing from his second-round match at Wimbledon in June.
He has been ranked as high as No. 9 in the world in early 2010 after reaching the semifinals at that year's Australian Open. Cilic is currently 24th.