Christophe Berra, Steven Taylor and Cole Skuse have all been ruled out of Tuesday’s visit to second-in-the-table Brighton and Hove Albion.
Berra and Taylor were both subbed during the first half of Saturday’s 1-0 win at Aston Villa and manager Mick McCarthy confirmed that they will miss the trip to the Amex.
"They’re both injured,” he said. "Steven Taylor’s got a hamstring injury which will keep him out for four weeks, I would have thought, and Christophe can’t play because he was concussed, so he’ll be back on Saturday.
"I think he’d like to play but I’ve said he can’t, that’s the rules, I’m not being held responsible for any subsequent damage which might happen. You can’t risk it.”
Despite losing two more centre-halves to injury - Adam Webster is already out for the season with an ankle problem - McCarthy says he’s not been tempted to hasten Tommy Smith’s return to the first team.
The New Zealand international will play his second U23s game at West Brom tonight having undergone back surgery in September.
"It would be wrong to rush Tommy back, he’s not ready for that,” he added. "Having spoken to him yesterday he never intimated to me that maybe he could go and play at Brighton.
"I saw him play for the U23s last Monday and he was fine, he got through the game but he’s not ready to play in the first team yet.
"And to risk that with all the games we’ve got coming up would be daft. He’s got to be fully fit.
"I’ve always thought Jonas Knudsen would make a great left-sided centre-back in a three, I think that’s a position for full-backs really if they’re a good size and they can head it.
"They’re happier going out defending one-v-one rather than centre-halves. That suited him and I thought Jordan Spence was excellent when he came on.”
He added: "I’ve always thought it was a position for full-backs. They have to go wide and play from there and me being a centre-half kind of recognises that.
"Rather than having to go and play wide in the right-back slot, I liked to stay down the middle, that’s what centre-halves do.”
The Town boss says Saturday’s goalscorer Emyr Huws is fine despite taking a knock at Villa Park.
"He got nasty bang on the knee, he’s got a bruised knee,” he said. "I’ve just spoken to him and he says he’s OK.”
But fellow midfielder Skuse won’t be back until the weekend due to the achilles injury he suffered against Reading.
"Skusey’s not fit, fingers crossed he’ll be fit for Leeds because we don’t have Toums for that game,” McCarthy continued.
Recently signed winger Danny Rowe could also be available for Saturday’s home game against Leeds.
"He’s got a groin strain,” McCarthy said. "I think he’ll be training on Thursday. He’ll probably be available for Saturday.
"He came in and he did really well in the U23s last week and if he’s fit he’ll be in the squad.”
"On-loan Reading striker Dominic Samuel is undergoing his rehab with the Blues having broken his toe in training on Friday.
"I haven’t seen him today, I came in a bit late because we were training later. The injured, the sick, lame and lazy were all in before me. I’ve seen his car, so he’s obviously here,” the Blues manager added.
"It is a blow, he came in, he looked good in training, he scored a hat-trick in the U23s and then he limped off on the Friday, broke his toe - six weeks out, I think.”
Better news is that Luke Hyam will play for the U23s this evening, his first game since suffering a knee injury in the pre-season friendly at Cambridge which eventually required surgery.
"I spoke to him on the way into training, just to wish him luck,” McCarthy said. "He’s had a big smile on his face, looking forward to the game, he’s quite excited by the fact that he’s going to get back playing.
"He may only do 60 minutes but knowing him he’ll attack it like he always does.”
The Town boss says the Blues have missed the 25-year-old’s tenacity and bite in midfield: "I remember going to Brighton last year, he was on the bench and Kevin Bru had run out of gas.
"I took him off and I put Luke on and he played in behind the strikers and he closed the defenders down, got about them and tackled.
"He can make a difference, his energy, his positivity and the way he plays. Fingers crossed he’ll be all right tonight.”
With the Brighton match the second of three in eight days is McCarthy tempted to make a few changes? "There’s the dilemma isn’t it? Don’t change the team, leave it and if anything goes wrong I should have freshened it up.
"Change it and it’s ‘Why the hell are you changing it when you’ve had a really good performance and won it?’. We’ll see.”
Jonny Williams (shoulder) and Giles Coke (knee) both also remain sidelined.