Leeds United have slapped a £10m price tag on disgruntled striker Alan Smith.
Birmingham made an opening bid of £5.75m for the England international after the Elland Road board appointed an agent to find potential buyers.
But Leeds director Peter Lorimer insisted Smith, 23, would not be sold on the cheap.
"When I see what Alan has to offer and what others have gone for, I put him as a £10m player in the current market," he told the Daily Mail newspaper.
He added: "Nobody has a bigger heart, he doesn't get injured and his temper is now under control.
"He's in control of his game and it's invaluable to a club to know you've got a real battler for 40-odd games a year.
"They talk about Michael Owen being valued at £25m. Nobody can tell me Alan isn't half as good as Owen, and everybody you talk to in the game cannot help but admire his attitude."
On Thursday, Leeds managing director David Richmond was forced to defend the club's employment of agent Phillip Morrison to explore the prospect of selling their star players.
But striker Smith, one of the club's most valuable assets, has insisted he will leave Elland Road on his terms and choose his own destination should they get relegated.
"If I have to leave - and that is not certain - it will be to a club of my choice," he said.
"I love this club and yet it seems they've appointed an agent to sell me somewhere I might not want to go."
Leeds are three points short of safety, with only three games remaining this season.
They are set to battle it out with Manchester City to avoid the final relegation spot.