McLeish wants the ensure that their Cup success this season does not take the steam out of the players in their battle for Premier League survival.
“It is great to be involved in the cup competitions at this stage,” said McLeish.
“But I hope it doesn’t take its toll in terms of our premier goal, which is Premier League status.
“My big craving is the Premier League. We definitely don’t want the cup runs to take the steam out of the players.”
The Birmingham boss added: “I know they have got enormous character but, when I look back at the last league game against Newcastle, we looked flat and short of inspiration.
“That is always the danger, that the longer the season goes, some minds become tired as well as the bodies. I think mental tiredness is the biggest concern.
“That’s why being able to recharge the batteries of a few of them this weekend was a Godsend. We left out a few players for next week’s final which should benefit us.”