The Hearts boss revealed one of the central defender’s grandmothers is Australian.
And he appeared to suggest Scotland could be in danger of letting him slip from their grasp if the 21-year-old is not given his breakthrough at full international level soon.
Souttar was due to win a first cap for McLeish’s squad during the summer tour of Peru and Mexico but was forced to withdraw before departure through injury.
He is set to drop back down to Scot Gemmill’s under-21 line-up after being named in the squad for next month’s Euro double-header with Andorra and Holland - although there is still scope for him to be selected by McLeish for the senior team’s Hampden clashes with Belgium and Albania.
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Asked if he thought his youngster was ready to challenge the likes of Aberdeen defender Scott McKenna and Celtic’s Jack Hendry for a place in the national team, former Scotland manager Levein replied: “He has been for a while.
“He’s got an Australian granny, you know that? I’m being serious.
“It’s not my call though. I just know he’s got an Australian granny, that’s all.
“I’m not in any way, shape or form trying to tell anyone who to pick for the Scotland squad. I had enough people trying to tell me when I was the Scotland manager.
“I’m just pointing the fact out, that’s all.”