The young centre-back is up against Aurélien Chedjou, Semih Kaya, Hakan Balta and Koray Gunter for a starting place in defence.
“There is always competition in football. It is a good thing for a player to have competition as it will make him stronger,” Denayer told Radyospor.
“I do not fear competition, it is good four our team.”
The Belgium international is understood to be keen to play Champions League football this season.
Denayer scored six goals and setup two assists in 44 appearances for Celtic in all competitions last season.
The 20-year-old who was voted Scotland’s Young Player of the Year last season, turned down ‘a number of offers’ in favour of Galatasaray according to SkySports.
Galatasaray are coming off the back of their first win of the season following a 4-1 victory over Konyaspor and take on Mersin Idmanyurdu.