Scot Gemmill has tested positive for Covid-19 but could return for the game in Kazakhstan on Tuesday.
Houston, who was part of Craig Levein’s Scotland set-up, has been assisting Gemmill for four years, while operating as a scout for Celtic.
The 63-year-old expects to be in full control with some decisions still to be made over the starting line-up.
"It was last Sunday when I got the call from Scot to say what his issue was and he is feeling much better today," Houston said.
“I’ve been through the process twice myself and I’ve actually been caught with someone else as a close contact, but Scot thankfully had flu-ish type symptoms, and I think that’s quite common amongst people who are catching covid nowadays post-vaccines, so Scot has had his vaccine.
"Knowing Scot he will be desperate to be involved but If I'm being honest, he will start targeting going to Kazakhstan on Sunday and I think he will be ready to travel because that will be over a week.
"He will test himself tomorrow and Friday but I don't expect him to be involved for the Turkey match.
"I have been with the under-21s almost four years and I know the preparation steps that Scot and I and the backroom staff have taken, we are in a set way with processes so we will just get on regardless whether he is here for Turkey, which is very doubtful, but certainly for Kazakhstan he will be back in charge."