Casemiro will only consider offers to leave Manchester United if he's told he does not have a future at Old Trafford, a source has told ESPN.
Galatasaray are keen to sign a midfielder before the summer transfer window in Turkey closes on Sept. 13 and are exploring the possibility of signing Casemiro on loan.
But the Brazilian is confident he will get opportunities to play at Old Trafford this season, despite the £50 million ($65.8m) signing of Manuel Ugarte from Paris Saint-Germain, and will only look to leave if he's told he is not in Erik ten Hag's plans.
Casemiro is on holiday amid the international break, but is expected back at Carrington next week ahead of the trip to Southampton on Sept. 14.
The 32-year-old was substituted at half-time during the 3-0 defeat to Liverpool on Sunday. He made two mistakes leading to Liverpool's first two goals, both scored by Luis Díaz, before being replaced by 20-year-old Toby Collyer.
Sources have told ESPN that while United will listen to realistic offers, Ten Hag and sporting director Dan Ashworth are conscious of weakening the squad ahead of what will be a hectic season.
United start their campaigns in both the Carabao Cup and the expanded Europa League after the international break and will have seven games in three weeks before the next break in October.
Casemiro's high wages would also present a problem for interested clubs, including Galatasaray. The former Real Madrid midfielder still has two years left on the contract he signed when he arrived in 2022.