Blues slipped to second-bottom after their last-gasp 2-1 defeat against Wigan on Saturday.
McLeish said: "At this stage of the season, you are looking to get the experienced guys into the team."
McLeish has been impressed with the contribution of youngsters Jordon Mutch and Nathan Redmond, who have both recently signed new contracts, but he knows his battle-hardened campaigners hold the key to City ensuring top-flight football for a third successive season.
"We have young Jordon in there and he's had a great couple of games for us," he said.
"But I don't want to have to rely on a young kid to steer us out of trouble. It's too much pressure on him.
"We've got guys who have got the experience and knowledge and it's important that they perform for us.
"It's about having those players available as well, of course. It doesn't help when they are injured or coming back from injury and trying to gain full fitness and sharpness."
McLeish's squad has been badly hit by injuries in recent weeks but he is hopeful of having more players available after the international break.