Club chief describes talk of offers being made as little more than speculation as he denies reports regarding a switch to England and says the attacker is not for sale
Mata, 23, has been linked with a move to England with Arsenal, Liverpool and Tottenham all thought to be monitoring the attacker.
However, Llorente believes the forward will still be a Valencia player once the window closes.
"We have no intention of selling him and we have not received any formal offers for the player," Llorente told Superdeporte.
"The news that has appeared in the papers is nothing more than speculation - Juan Mata is not for sale," added the president.
Llorente went on to say that his plans are to bolster the squad rather than break it up.
"Our plan this summer is to make our squad better and our priority at the moment is to bring in a central defender," he said.
The Spain international was part of the side that won the recent European Under-21 Championships in Denmark and is reportedly worth around £17.5 million.