Forward Szmodics has missed the last four games through illness, while striker George Hirst has been sidelined for the last three with a groin injury.
Asked if either could return to action this weekend, McKenna replied: “Not George Hirst. Hopefully he’ll be back in training next week. Sammie, yes, he trained with the group this week, so it will be good to have him involved with a game. Obviously you have to make a decision on minutes, because he missed a couple of weeks of training and hasn’t started for quite a while. We’ll make a judgement, but it’s going to be good to have him back in the squad.”
Meanwhile, the Blues boss confirmed that academy graduates Elkan Baggott and Finley Barbrook will also both be in the squad.
Baggott, 23, has acted as Town’s fourth choice centre-back so far this season, while holding midfielder Barbrook, 21, recently returned from a loan spell at Lincoln City where his game time was limited to the EFL Trophy.
Asked if last weekend’s game at Portsmouth being postponed would affect his team selection, the Blues boss said: “Maybe a little bit. Probably in a couple of instances. There might be some players that we think would really benefit from the rest and some players we might think who will benefit from the rhythm of going again and keeping the flow of minutes in their legs.
“And there are some players who maybe haven’t played as many minutes, who it’s really important for us to get minutes into on Saturday. We’ll take a sort of balanced view of it.
“We’ve picked a team that I think reflects our desire to go through in the Cup, but also reflects the primary goals of the season and the importance of getting the balance of the minutes right across the squad.”