Middlesbrough boss Tony Mowbray has admitted the club cannot afford to let defender David Wheater leave for nothing next summer.
The Redcar-born player, who is out of contract at the end of the season, is being tracked by a series of potential suitors, with Everton understood to be among them.
He would be able to leave Teesside on a Bosman free transfer during the summer, but Mowbray believes Boro need some return on their investment.
He said: "You look at David Wheater and you have to look at the contractual side of where we are as a football club. He has got six months to go. He's a player who has openly said he's a huge Boro fan, his family are huge Boro fans and he would love to be here.
"But he wants to play in the Premier League. In an ideal world, he plays in the Premier League with this club, but we are not in a position to give him that at the moment.
"The scenario we wouldn't want is for him to stay here and spend the next six months playing for our team and then walk away for nothing. He is a player that this club has nurtured and brought up through the Academy.
"He has given us a lot of good years, of course, but I think it works both ways. We find ourselves in a situation where we need something back for a player that we can try to re-invest back into the team, potentially, rather than him walking away on a Bosman."