European weightlifting champion Daniyar Ismayilov faces being stripped of his title after failing a drug test.
Ismayilov of Turkey was the Olympic silver medallist in the 69kg category in 2016 and won the European title at 73kg in April.
He was not on the entry lists for the upcoming Games in Tokyo when they were published this week.
Ismayilov is provisionally suspended after he tested positive for a banned substance, Turkish officials said.
Officials did not name the substance involved or give a date for a hearing.
Turkey's Cumhuriyet newspaper reported Ismayilov gave the sample before winning gold at the European championships in Moscow in April.
Ismayilov is the second current European weightlifting champion to have been suspended for a doping offence in the run-up to the Olympics.
Dmytro Chumak of Ukraine, who competes at 109kg, was suspended after he allegedly tried to bribe an official sent to test him in May, the International Testing Agency said last month.
Ismayilov represented his native Turkmenistan at the 2012 Olympics and switched allegiance to Turkey before the 2016 Games.
He is the second medallist in his category to test positive.
Rio bronze medalist, Kyrgyzstan's Izzat Artykov, was disqualified following a positive test for the banned substance strychnine.
Turkey has been under pressure over its record on doping.
The country was restricted to entering only one male and one female athlete for Tokyo weightlifting because of past doping offences.
Former Turkish federation president Hasan Akkus, now president of the European Weightlifting Federation, was charged last month with tampering with the anti-doping process after he allegedly manipulated records to change the jurisdiction of 17 Turkish doping cases in an attempt to dodge restrictions on the country's team.
Australian Associated Press
