Chelsea fear losing young striker Dominic Solanke.
The Daily Mail says they have reached an impasse over a new deal.
Solanke, 18, has one year left on the contract he signed in September 2014 and has so far rejected the club's efforts to agree a new one.
It will be a bitter blow if Chelsea are to lose Solanke, long since identified as one of the academy products capable of bridging the void into the first-team.
Jose Mourinho once offered to shoulder the blame if he did not go on to play for England at senior level.