Mark McGhee has admitted that four players withdrawing from the Scotland squad through injury is disappointing but said the challenge is for others to step up to the plate against Malta.

Kieran Tierney, Leigh Griffiths, Kevin McDonald and James McArthur all left the squad with Hearts forward Tony Watt and Rangers defender Lee Wallace called up as replacements.

"We've got to make sure it's not a blow," McGhee said. "We've got other people here that will step up.

"You pick what you think is the best squad for the occasion so clearly losing four of them immediately is disappointing but we have to ask others to step up.

"It gives other people an opportunity."

One player who could be given a chance to shine is Watt, who has impressed for Hearts in the early weeks of the season. Picked out by Gordon Strachan as a potential star earlier this year (http://stv.tv/sport/football/international/1346013-tony-watt-could-be-scotlands-zlatan-says-boss-gordon-strachan/), Watt was also on the receiving end of a rebuke from McGhee in March when the Scotland assistant said he didn't train hard enough and had to prove he could be trusted with a role in the national team, despite his ability.

McGhee now believes that trust has been earned after in-depth discussions with the player.

"We've been big fans of Tony since we first saw him," he said. "We brought him in for a training camp early and he had certain issues at that time.

"It's funny, I had a couple of conversations with Tony over the summer, quite long conversations, and I reported back to Gordon [Strachan] that what I was hearing was responsible, mature and there was a change, in a sense.

"It's no surprise to me that he's doing well where he is and he's at a level now where we can bring him in. He offers something a little bit different. We're delighted to have that type of player in the sort of form that he's in now.

"He had his injury last season and that set him back a little bit but he should be capable of holding a place down in some of the teams down there as well. It's irrelevant really where he's playing, the important thing is that he is playing.

"I've also had conversations with [Hearts director of football] Craig [Levein] about him and how they handle him.

"I think they're doing a brilliant job with him, giving him a bit of freedom and not trying to change him.They're just trying to encourage him and emphasise what his abilities and strengths are.

"I think that's done him the power of good."