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.
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.
"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."