Head coach Liam Manning has confirmed that Jeffrey Schlupp is expected to be out long-term but is awaiting the results of a scan to determine just how long.
The full-back picked up a hamstring injury during the 1-1 draw against Sheffield Wednesday, joining fellow left-sided defenders Lucien Mahovo, Ben Chrisene and José Córdoba on the treatment table.
"He's scanning today so we'll find out the extent of the damage. It doesn't look good. If you look at hamstrings, the more serious ones are usually months. He's had surgery on the one on that side before," Manning explained.
"He'd just started showing what we signed him for, so it's disappointing for him and for us. We're crying out for leaders, for personality, he'd started to bring that in recent weeks. That's easier to do when he's in the team, finding form and playing a bit better.
"Everyone else is OK from Wednesday night."
"Neither of (Ben and Lucien) are available, possibly after the international break but they're not ready at the moment. A similar timeframe for José, Jack (Stacey) has progressed through the protocols but tomorrow will be too soon to return. He'll be available for the first one after the international break.
"Both are out on the grass and progressing well, Gabe (Forsyth) had a minor set-back but he's out on the grass working. Anis (Slimane) is back out there too which is always a positive to see."
With a long list of players currently absent through injury, Manning reinforced how much work is going on behind the scenes to identify any causes.
He also outlined the potential opportunities that this has presented for academy players to join the first-team environment.
"Some injuries, you can pinpoint the exact reason. Other ones, it's much more difficult. I've never had such a high number for a sustained period," he added.
"There's a lot of work going into finding out why - we're investigating workload, training programmes, cause of the injury. It's frustrating and makes it challenging with who you have available or when you have a heavy week. We need to get to the root of the problem.
"Errol's (Mundle Smith) someone who has been training with us for a while, he spent time with us in pre-season. Theo (Adelusi) is another one who has been on the bench and been around it, they've adapted well to training with the first team."
After gaining a point at Hillsborough, City have stopped a run of six consecutive defeats but has demanded more from his squad against Leicester.
The head coach urged his players to get the fans onside from the off, as was the case against Hull City last weekend.
"The other night, we stopped the run of defeats which is important. Was the win we wanted? Of course not. We need to take that into the weekend, show a level of fight and intent. We need to be smart with how we play, territory and where we play is so important.
"I'm always honest with you guys. If I was a fan, how would I feel? I get the frustation, the anger, all of it. Against Hull, I thought the fans were outstanding getting behind the lads first half. We need to sustain that when we face a little adversity and shift it back in our favour to keep the fans with us.
"You're not going to be perfect every time but the fans need to see us showing intent, playing forward, playing with aggression."