Naismith was injured in yesterday's Scottish League Cup final win over Celtic at Hampden and did not join the rest of the Scotland players who flew out from Glasgow for a week's training camp in Spain.
Goalkeeper Cameron Bell has been drafted in as a replacement for Iain Turner who called off with injury over the weekend. Scotland assistant Houston said: "Steven has a hamstring and groin injury from yesterday and Iain Turner is also out.
"Phil Bardsley and Scott Brown, who took a knock yesterday as well, are joining us but we will need to assess them over there. We will look to see if we need to bring anyone else in and Craig (Levein) and I will discuss it."