The "numbers would need to be considerable" for James Tarkowski to leave Burnley during the transfer window, says manager Sean Dyche.
The defender, 27, has been the subject of three bids from West Ham, with the most recent thought to be around £30m.
Burnley are yet to start their Premier League campaign and have not made any signings since finishing 10th last season.
"We want to keep our best players," said Dyche.
"I don't see why any player would leave here at this moment in time and if they did I think the numbers would need to be considerable for it to be considered.