West Brom midfielder James Morrison has been forced to withdraw from Scotland's get-together at St Andrew's this week because of a hamstring injury.
The 22-year-old recently had a spell on the sidelines because of the problem and is still not fully recovered, according to boss Tony Mowbray.
The Baggies manager said: "I spoke to George Burley on Sunday night to explain James' situation.
"We've had to ease James back in and he's only had a few days' training since his injury.
"He needs to spend time at the club strengthening up the areas of his leg in which he's been feeling tight in recent weeks."