Irtegun, who played for six years for Fenerbahce before joining Istanbul rivals Basaksehir in 2015, had been taken into police custody as part of the investigation into the group of US-based Islamic preacher Fethullah Gulen.
He was freed after giving testimony to prosecutors, the state-run Anadolu news agency said. Irtegun is barred from leaving the country.
Turkey accuses Gulen of masterminding the coup bid from the United States and leading a group Ankara calls the Fethullah Terror Group (FETO). Gulen denies the charges.
Irtegun’s passport was confiscated when he tried to leave the country two weeks ago and Basaksehir have already annulled their contract with the player.
The defender, 33, has appeared ten times for the Turkish national side.
He is accused of downloading and sending messages through the Bylock messaging app which authorities suspect was used by Gulen’s supporters to coordinate the coup plot, according to press reports on Friday.
Over 50,000 people are being held under arrest in the wake of the coup plot, in a crackdown that has caused international controversy.
The crackdown has also touched football with the authorities issuing an arrest warrant for former star footballer Hakan Sukur who played a key role in Turkey’s glorious run to third place in the 2002 World Cup.
Sukur, also a former a stalwart for Galatasaray, is now based in the United States.
Authorities last year also arrested former football star Ismail Demiriz, who played for Galatasaray from 1984-1993 as well as 27 times for the Turkish national side. He was released in February.