Sunderland defender Lamine Kone has told manager David Moyes that he wants to leave the club.
The 27-year-old Ivorian, who is a target for Everton, joined the Black Cats in January and helped them avoid Premier League relegation last season.
Kone says his decision comes after the club failed to offer him the improved deal that they said they would.
“It is therefore with much regret that I can only assume that I do not figure in David Moyes’ future plans,” he said.
“With that being the case, it is with much sadness that I have asked the manager and the chief executive to be allowed to leave Sunderland.
“However, until that time, I give my word that I will give my utmost in training and on the field.”
Sunderland begin the Premier League season away to Manchester City on Saturday at 17:30 BST.