Roberto Martinez has insisted that Everton's John Stones will not be going anywhere in January.
The highly-rated centre back was the subject of intense interest from Chelsea in the summer, but the Toffees held firm despite several big money bids and a transfer request from the player.
Chelsea's slumping fortunes since then have fuelled further speculation over Stones but Martinez's stance has not changed.
"It doesn't matter if Chelsea come back in for him. We created a squad to see how far we could go over 10 months. January doesn't come into consideration," he told several newspapers.
"We'll never lose anyone in January - unless it's somebody who hasn't been playing and we need to find a solution. If he's a top performer, it's not even a consideration."
Chelsea's defeat at Leicester on Monday night was their ninth in 16 matches as their poor start to the 2015-16 campaign continued.
Stones' assured displays for the Toffees have led to him being tipped as a solution for Jose Mourinho's ailing Premier League champions, but that would leave Everton with a huge hole to fill in the heart of their defence.
"When you are right in the middle of a season, I think players understand that you can't sell someone if you can't replace him," Martinez added.
"I think the uncertainty comes in the summer, where everyone speaks about possibilities.
"January is a window to solve problems with players who are not featuring as often as they feel they should, or to bring in players from a lower league to give them an opportunity."