Championship leaders Newcastle have reportedly made three bids for Beckford, who played the full 90 minutes of Leeds' 1-1 draw with Wycombe Wanderers on Saturday, while West Brom are also pondering a bid for him.
Speaking after the Wycombe game, Grayson confirmed that he would not be prepared to let the 26-year-old quit Elland Road in the transfer window unless a suitable offer comes in.
"As a footballer, you can only leave when your contract expires or you are given permission to go," said Grayson.
"We've said all along that while he's under contract, we'll dictate when he leaves the football club. That's why you sign contracts.
"Putting in a transfer request doesn't guarantee he'll get a move. Until someone meets our valuation, he'll stay here."
Grayson is also unhappy that news of Beckford's transfer request was made public - and he feels the prolific hitman has been poorly advised.
The Whites boss added: "It was a surprise and a disappointment for the news of the transfer request to come out. We try to conduct our business as quietly as possible, whether signing players or letting others go.
"Whoever advises him has decided it is the best option to go down. I think he has been advised wrongly but, whether that is right or wrong is irrespective, as it has happened."
Coca Cola League 1 Top Goalscorer 2009/10: Beckford, J. 5/2