Neil Warnock believes Ross McCormack has not been called up to the Scotland squad because it is difficult to fit the striker into a winning system.
The Aston Villa striker was not included in the squad to face Malta on Sunday, despite Celtic's Leigh Griffiths pulling out with injury.
Warnock, who managed McCormack at Leeds United, has sympathy for both the player and head coach Gordon Strachan.
"It was very difficult to find a system to suit Ross McCormack," said Warnock.
"I couldn't play him up front because he wasn't big enough or good enough in the air.