Blues striker George Hirst is set to return to the squad for Sunday’s FA Cup tie at home to Bristol Rovers and Ben Godfrey will make his Town debut, while Omari Hutchinson might be back as soon next week, but Sammie Szmodics has joined the injury list having picked up an ankle problem.
Hirst has been out since the 2-1 win at Tottenham in November with a knee injury, but McKenna says the 25-year-old is likely to play a part from the bench against the Gas.
"George has got a chance to be involved,” he said. "It won't be for a big chunk of the game, but he's trained with the group today. I have to say it's a big bonus for us.
"Even just having him back in around the group feels like a big boost. Hopefully, if everything goes well tomorrow in training, then he'll be available on the bench for Sunday. If it fits right, then possibly able to get some minutes.”
Conor Chaplin remains sidelined for a few more weeks with his knee problem, while Szmodics picked up his problem last weekend.
"Sammie Szmodics has an injury after the Fulham game,” McKenna continued. "He did it in the Fulham game with a tackle and did very well to play through, but he's going to be out for we don't know how long, to be honest.
"Hopefully, it's not a very, very serious injury, but he's in a boot at the moment. There’s some damage to his ankle, so he'll be assessed on Monday to get a little bit of a clearer picture of where he's at.
"But those two boys and Omari Hutchinson, as well as the longer-term injuries like Axel [Tuanzebe] and Chieo [Ogbene], won’t be available.”
McKenna says Hutchinson isn’t too far away from a return from his groin problem: "He'll certainly be back, if everything goes well for the Liverpool game, the Brighton and Man City games we're going to have to make judgments as we go along.”
The Blues boss confirmed that new signing Ben Godfrey will make his debut for the club
"He's good, he’s ready, he's been training very hard,” McKenna said. "Atalanta are a team that do train very hard.
"Of course, he hasn't had lots of match minutes lately, but he's looked fit and ready in training. He's fitted in with the group really, really well, as we expected he would, and he'll be involved in the game on Sunday.”
McKenna confirmed that midfielder Massimo Luongo is fine having been ill over the Christmas period.
The Blues boss isn't planning on drafting any of the U21s into the squad.
"I think, at the moment, we have strong numbers and lots of players who need the minutes.
"We have to make sure that we have a group there that is ready to go and deliver a really good performance.
"There are still quite a few U21s who are training with us on a regular basis and doing well. But I think unless we have any injuries, then it would be likely the senior boys that would be involved on Sunday.”