CNN Turk said Irtegun, a former Fenerbahce and Basaksehir defender, is accused of being a sympathiser of U.S.-based cleric Fethullah Gulen, whom Ankara blames for orchestrating the abortive coup.
The footballer was detained by police for allegedly using ByLock, an encrypted messaging app the government says was used by Gulen's network, which the government calls FETO and considers a terrorist organisation, CNN Turk said.
Reuters was not immediately able to reach Irtegun and Turkish officials were not immediately available for comment.
Irtegun's contract with last season's runners-up Basaksehir was cancelled in the off-season, and the player was barred from leaving Turkey earlier this year, the news report said.
Irtegun provided Turkish authorities with the names of the people he had been in contact with over Bylock, and later turned himself in at Istanbul police headquarters, CNN Turk said.
The 33-year-old had stints at Gaziantepspor, Fenerbahce and also played for Turkey, both in the youth and regular squads.
Since the failed putsch, some 150,000 people have been sacked or suspended and more than 50,000 detained, alarming Turkey's Western allies and rights groups, who say President Tayyip Erdogan is using the coup as a pretext to muzzle dissent.
The government, however, says the measures are necessary due to the gravity of the threats it faces.
(Reporting by Tuvan Gumrukcu; Editing by Robin Pomeroy)
