McLeish admits he has been hit by the worst injury crisis of his four seasons in charge of the Carling Cup winners.
Lee Bowyer, David Bentley, Keith Fahey, Stephen Carr, Liam Ridgewell, Craig Gardner and Nikola Zigic are all rated doubtful.
Alexander Hleb, plus long-term casualties Scott Dann and James McFadden, are definitely ruled out.
McLeish will take a late decision on whether to include Barry Ferguson who has had an injection to ease the pain from his broken rib.
David Murphy is dreaming of playing at Wembley in the FA Cup for Blues - a year after fearing his career could be over.
The Blues left-back missed all of last season after rupturing a knee cap and has been understudy to Liam Ridgewell during the current campaign.
He could only look on as Blues lifted the Carling Cup a fortnight ago.
But Murphy has featured in the FA Cup and is in line to start against Bolton.
Murphy told Press Association Sport: "I did wonder if I would ever get back fully fit again.
"When the injury initially happened, it was at the end of the season so you've just got to go away and recuperate.
"But I would say after Christmas time just over a year ago, when I was looking to push back in the side and had a setback, that was the worst part.
"There were a couple of setbacks along the way and I spoke to the surgeon but thankfully we resolved the problem and, touch wood, I haven't had a problem with the knee for a year now.
"For me, to have the chance to get to Wembley is extra special after the injury.
"The FA Cup is one of the major competitions in the world. Everyone watches it and to play in an FA Cup final or semi-final would be fantastic.
"It is just great to be back playing and back involved all the time. I'd love to get more game time but we will have to see what happens."
Bolton boss Owen Coyle has no fresh injury worries.
Chelsea loanee Daniel Sturridge is cup-tied, which could open the way for Ivan Klasnic, who has scored the winner in the last two rounds.
Ricardo Gardner joined Preston on loan this week after recovering from a knee injury while Jlloyd Samuel (thigh), Zat Knight, Sean Davis, Joey O'Brien (all knee) and Sam Ricketts (Achilles) remain on the sidelines.
Klasnic has fired Bolton into the quarter-finals, but even the Croatian is not guaranteed a starting spot.
Klasnic has found himself below captain Kevin Davies, Johan Elmander and Chelsea loanee Daniel Sturridge in the pecking order this season.
But the Trotters' FA Cup run has given the 31-year-old a chance to show his qualities and he repaid his manager's faith with the winning goals against Wigan and Fulham in the last two rounds.
Klasnic made his mark in the Barclays Premier League last week, too, coming off the bench to net the deciding goal in a 3-2 win over Aston Villa.
Coyle has made a number of changes for FA Cup matches this season, with goalkeeper Adam Bogdan also an ever present so far, and the Bolton boss must decide whether to revert to a full-strength line-up at St Andrew's.
The Scot said of Klasnic: "He's put himself in contention, as have the other 18 players. Regardless of who scores the goals for us, it's very much a team effort and they're all buying into that.
"Ivan's done fantastic, not only on Saturday but also scoring the winning goals at Wigan and Fulham, so he's certainly done himself no harm. He's looking 100% fit, he's looking sharp and we know he's a terrific goalscorer.
"I'm always looking to pick the best team possible. Daniel Sturridge is cup-tied so there'll certainly be a minimum of one change. There may very well be a few more on top of that."