Alex McLeish claims it would take a substantial bid for Birmingham to contemplate selling James McFadden.
The Scottish international has become the centre of transfer gossip of late following the Blues' relegation from the Premier League last season.
He had been tipped to make a switch back to the top flight, but his manager has ruled out any possibility of that happening.
McLeish insists that the club are under no pressure to sell their top players and insinuated that any club wanting to lure McFadden away from St Andrews would have to dig deep.
"He'll stay at the club," the Blues boss told Sky Sports News.
"Unless someone comes in with a bid relative to the Manchester United bid for (Cristiano) Ronaldo then James is going to stay put.
"I think to put it succinctly he's not for sale."