Everton's John Stones has handed in a transfer request in an attempt to force through a move to Chelsea, according to Sky sources.
The 21-year-old defender has been the subject of three separate bids from Chelsea, including one for £30m, all of which have been rejected by Everton, who insist he is not for sale.
However, the England international has now submitted a formal transfer request in a bid to end the stalemate.
Toffees manager Roberto Martinez is keen to keep Stones at Goodison Park this season and has refused to answer questions about the proposed transfer.
"There is nothing to comment on that," said Martinez on Tuesday.
"Once more, it is always the same question and always the same answer.The only thing that matters now is the game we have in front of us. There is nothing to announce or discuss.
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"I know it is your job to keep asking the same question and unfortunately it is my job in this case to always give you the same answer."
Stones was due to face Barnsley, the club where he began his career, in the Capital One Cup on Wednesday.
However, it is now unclear if he will be included in the Everton squad for the second-round match at Oakwell.