Sunderland are anxiously awaiting a response from promising Irish midfielder Thomas Butler on their latest offer of a new deal.
The 21-year-old is now out of contract but the Black Cats have presented him with a series of improved offers which are yet to meet his requirements.
However, the club remain hopeful of persuading the Republic of Ireland Under-21 international, who made his senior debut at Charlton last season, that his future lies at the Stadium of Light.
"Thomas has been offered a number of vastly improved terms by the Black Cats but has turned them down," said a club spokesman.
"The club is now waiting to find out whether their latest contract offer will be accepted."
If Butler does not re-sign, Sunderland would be entitled to compensation from his future employer because of his age.