Gareth Southgate admits Middlesbrough would not welcome any bids for David Wheater after reiterating the defender is not for sale.
Wheater is among the players to have been linked with a move away from the Riverside this summer following Boro's relegation from the Premier League.
The 22-year-old has pledged to stay at Boro this season and Southgate is looking to build his team around the likes of Wheater, who is confident of being fit for the opening game of the season against Sheffield United after undergoing keyhole surgery.
"David's not for sale," said Southgate in the Daily Express. "He and Matthew Bates, who has also committed himself to the club, are the types in terms of quality, hunger and desire that we want.
"We have to build our team around those types of characters. We have to make sure the dressing room stays tight through a period that could involve a lot of speculation.
"We wouldn't welcome bids for David. The key is that he has expressed his desire to stay. The agents that work with him have been very supportive in that and that's been refreshing for us as well.
"One of the next stages is for him to develop his leadership skills. People look at centre-halves and want good communicators. They want guys with physical stature, but who have leadership abilities, and we have to work at that.
"He has shown his ability and, with experience, that leadership will start to emerge."