Hleb has struggled for fitness since his temporary switch from Barcelona in August and has failed to make a significant contribution.
He has been left out of the City starting line-up for the last two matches with Stoke and Manchester City and is unhappy with the situation.
Show us what you're made of: Birmingham boss Alex McLeish has issued a challenge to struggling Hleb
McLeish said: 'Alexander wasn't happy at not playing and I was delighted he wasn't happy.
'I'd hate to think that a player of his calibre at this stage of his career doesn't want to make an impact any more.
'He should be wanting to maintain his reputation as a top-class player, a world-class player.'
McLeish added: 'He started to look like the player we know he can be when he came on at Man City.
Damp squib: Hleb has yet to shine during his loan switch from Barcelona
'We have to get him top fit. He's had injuries, he's missed training.
'He's a guy who has got to be in our team most weeks, unless I do something tactically.
'But he can bring a level where it can help us create chances.'
Up your game, Alex! Loan star Hleb still not fit, says Birmingham boss McLeish Foster and Hart are the new Shilton-Clemence for England, says McLeishBIRMINGHAM CITY FC