Hughes and Cowie will join with the rest of the squad in London for the flight to the Far East.
Burley had already suffered eight call-offs in the build up to this weekend's match, with Scott Brown, Shaun Maloney, Danny Fox, Kevin Thomson, Steven Naismith, Robert Snodgrass and Garry O'Connor having all withdrawn from the squad.
Scott Robertson of Dundee United was brought into the fold briefly but he too succumbed to injury and will not make the trip.
Scotland lost a number of key players to injury even before the squad was announced last week, with James McFadden, Ross McCormack, Chris Iwelumo, Kenny Miller, James Morrison, Kris Commons and Gary Naysmith among those unavailable.
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