Liam Manning has confirmed that Marcelino Núñez will be out for a number of weeks after sustaining an ankle injury in the win at Portsmouth.
The Chilean midfielder picked up the injury in the first half at Fratton Park and returned after the break, but lasted just five minutes into the second half.
"There's a bit of swelling, he tried to continue but was unable to. We've had a look at it and it'll be a matter of weeks not months. Watching back the video, it was a bit of a nasty one. It's disappointing, I thought he was excellent in the first half against Portsmouth and on Tuesday at Watford as well," Manning said.
The City boss did provide some good news on the impending returns of Kenny McLean, Lucien Mahovo and Gabriel Forsyth.
McLean underwent surgery during pre-season while Mahovo and Forsyth have been absent since last season.
"We've seen bits of Kenny in training this week, we've got the depth, we've got the options. It's one of those, the work he had done on the ankle is OK, it's now the conditioning bit.
"He's had the best part of 12 weeks with limited work, we'd like to get him back as quickly as we can but we'd also like to keep him back.
"I'm expecting Lucien back training during the international break, Gabe's a bit later than that but progressing really well. They're lads I'm looking forward to working with and having back within the group."
Following on from the win against Portsmouth, City's first league victory of the season, Manning said he was pleased with some of the aspects of the performance.
However, he also outlined room for improvement in how his side managed a second half where the home side offered more aggression as they chased the game.
"First half, it was really good control, elements similar to Millwall first half, we got two excellent goals off set-pieces that we had worked on," he explained.
"The physicality we showed on set-pieces, especially defensively second half, putting everything on the line to get three points. It's difficult when you're ahead and teams are chasing, coming out more aggressive. It's game three and we'll continue to impress, improve and grow.
"We have to keep working at it, refining and improving. The second you think you've cracked anything, I think you're in trouble. We'll keep working and revisiting it, improving with the ball but we have to be clear when we can't do that, what it looks like."
This weekend sees Middlesbrough come to Carrow Road in the third game of the season, while Southampton are the visitors to NR1 next Tuesday in the Carabao Cup.
Now under Rob Edwards, Boro have started their league campaign with wins against Swansea City and Millwall either side of a shock 4-0 defeat at home to Doncaster in the Carabao Cup.
"(Their start) doesn't surprise me, there's elements of consistency to their team, not a huge turnover. We'll make sure we're prepared and planned for what we expect them to do. We'll take some of the positives from the opening three games, we'll look at our fundamentals and make sure that we deliver those."
Manning also held special mention for the club's travelling support over the past week with packed away ends at both Vicarage Road and Fratton Park watching City come out on top on both occasions.
He now wants to multiply that at Carrow Road for the upcoming games.
"We're delighted to get back here. I have to say I thought the travelling fans last weekend were electric, now we can times that by 10 with over 20,000 here. We'll show that fighting spirit and togetherness.
"We want everybody pulling in the same direction. You could see the appreciation from the players and the staff afterwards, we all felt the last 10 minutes. When the board went up and seeing it, probably muttering a few expletives.
"The reality is we're going to have good times and bad times, we won't make excuses, we'll be open and honest. We'll keep pushing in the right direction and it's much more powerful when we're all doing it together."