Simon Grayson has warned Sunday's opponents West Ham they must at least treble their offer for Max Gradel if they are to tempt Leeds into a sale.
The Leeds boss confirmed the Hammers made a move earlier in the summer but their offer, believed to be in the region of £2.5million, fell well short of Leeds' valuation.
The two sides meet at Upton Park this weekend, with Gradel back in first-team contention following a one-match ban after being sent off against Middlesbrough.
"West Ham made an offer for Max this summer, but it was not acceptable," Grayson told The Sun.
"Will he want to show West Ham what they are missing? Every time a player pulls on the shirt, you want him to play to the maximum of his ability - and that's the case with Max.
"If he goes out there and scores a hat-trick and they come back in with three or four times the money they offered previously, then it'll be something to think about."
Gradel is in the final year of his contract at Elland Road, but claims new terms have yet to be offered, though Grayson is unconcerned by the doubts surrounding his future.
He said: "Max loves playing for this club, and it was never a concern that he'd leave because West Ham's valuation of him was nowhere near ours."
West Ham are the favourites at Upton Park on Sunday, with many backing Sam Allardyce to lead the club back to the Premier League in his first attempt.
Grayson, though, has high hopes his side, who registered their first win of the season against Hull on Tuesday, can upset the odds.
"Hopefully, we can go out there and become coupon busters," said the former Blackpool manager.
"It is their remit to win promotion at the first time of asking, but I know we have a team who are capable of beating anyone on our day."