Tony Mowbray has reiterated that David Wheater will only leave Middlesbrough during the January transfer window for the right price.
Wheater is out of contract at the end of the season and is expected to be sold by Boro next month to ensure the defender does not leave for nothing.
A clutch of Premier League clubs are tracking the 23-year-old and Mowbray is resigned to the home-grown product moving on.
Mowbray has received tentative interest in the centre-half, but he is determined to ensure Boro receive a fair fee for Wheater.
"We have had a few tentative calls already about David," Mowbray admitted to the Evening Gazette. "Obviously the transfer window isn't open yet, but there is interest there already, so we will wait to see what develops.
"People keep asking about David and talking about where he will be at the end of next month. From my point of view I'm absolutely delighted that he has not let all of this affect him and continues to produce special performances for us.
"He's a valuable asset but we know that he is out of contract in the summer and can walk away for nothing. We don't want that to happen because when you've got a valuable asset you need to cash in if you can when he leaves the club.
"But we have to try to stick to our valuations, too. We know what we are looking for, and so we will wait to see what January brings."