Scotland assistant coach James McFadden has urged Alex McLeish's new recruits to seize their chance with the national team as they may only get one opportunity.

Seven players have been handed their first senior call-ups as McLeish kicks off his second stint as boss with a friendly double-header.

McFadden, who won 48 caps for his country as a player, has taken up a coaching role under the new regime.

After overseeing his first training session alongside McLeish and fellow assistant Peter Grant, the 34-year-old urged the nation to be positive about the next crop of talent coming through.

McFadden also had a message for the youngsters, challenging them to grasp their opportunity as the international landscape can change in the blink of an eye.

He said: "We talk our game down, if we could get awards for talking our game down we'd win that.

"We need to start talking it up and bring that belief that young players can come in, impress and express themselves.

"I was one myself and I didn't listen when people said you couldn't do stuff, I want them to come in with that attitude, to think I'm going to be the man and I'm going to achieve something for Scotland.

"There are guys coming in here at 20, 21, 22 and when you're in the environment you don't really think too far ahead, you think 'if I don't make this one then I'll make the next one'.

"But you might only get once chance at it, the next one doesn't come and before you know it you're sat here as a coach saying we really should have qualified but we never.

"For the young boys, don't be looking too far ahead and thinking 'I'll play it safe and get the next one'.

"This is the chance to cement your place in the squad.

"You've got to take your chance when you get it, you don't know when the next one will come."

Scotland mainstays including Christophe Berra have been omitted from the squad to face Costa Rica and Hungary.

McFadden, however, dismissed the notion that this could signal the end for some of the nation's more experienced players.

Instead, he insists it is to give the management team the opportunity to appraise how well untested players can cope with the rigours of international football.

He said: "We need to see that they're good enough. Most of them are playing every week for their club and playing really well, it's great to see.

"But it's a step up to become an international so we have to look at them and see what they are like in matches.

"We aren't going to just throw caps, they are only for guys we feel deserve it."

He added: "We know what the guys who played in the last campaign can do, we aren't saying they aren't good enough but we know what they can do.

"Certainly, Christophe is an experienced player and we know what he can do.

"We've quite a lot of left-footed defenders, which is really unusual, so we have to find a balance in the side.

"To bring Christophe when you are trying to see other players, is it fair?

"That's not to say that come the first game Christophe won't be involved in it."