John Obi Mikel faces a battle to stay with Chelsea.
The Sun says he is wanted by Turkish champions Galatasaray in a £13million deal.
The Nigerian midfielder only signed a new five-year contract in December and has never expressed any desire to leave London.
But the return of Jose Mourinho has cast doubts over Mikel's long-term future and opened the door for Galatasaray to make their move.
Mikel, 26, bought for £16m eight years ago, fell out with Mourinho over his poor time-keeping during the Special One's first spell in charge at Stamford Bridge.