Leigh Griffiths' unhappiness at a lack of game-time for Scotland is a "great thing", says assistant coach James McFadden.
Manager Alex McLeish had confirmed Steven Naismith was his first-choice striker, leading Griffiths to describe the decision as a "kick in the teeth" and pledge to work harder to displace the Hearts forward.
McFadden was delighted by Griffiths' reaction to the selection of Naismith, who scored in Scotland's Nations League 2-0 win over Albania.
"It's a great thing. You want competition, I want guys that are unhappy not to be playing and that's right," McFadden said.
"We want Leigh Griffiths and other guys coming back in, we want them to be disappointed, we want them to pick up the challenge because there are places there for everyone.
"It is a challenge for Leigh. He has a similar challenge at club level and he will have to fight the battle to get into the team both at Celtic and for Scotland.
"But that's what we want. If he's unhappy, great. If he comes with the attitude he wants to come and show he should be in the team, even better."
Griffiths has gained 19 caps for Scotland and scored four goals. Scotland face Israel on October 11 in a League C Group 1 match at the Sammy Ofer Stadium, live on Sky.