Scotland have concerns over the fitness of several defenders ahead of their opening 2014 World Cup qualifiers against Serbia and Macedonia.
Southampton left-back Danny Fox, Norwich's Russell Martin and Celtic's Charlie Mulgrew all reported to Scotland's Mar Hall base with injuries.
Wolves centre-back Christophe Berra was away from the squad as he awaits the birth of his first child, which is due on Tuesday.
Assistant manager Peter Houston said: "Danny Fox has a groin strain, Russell Martin has an ankle knock and Charlie Mulgrew's Achilles is still a bit sore.
"He missed Saturday's game for Celtic. The good thing is we have got a few days, sometimes injuries settle down after 48 hours. We'll keep everyone informed."
Besiktas goalkeeper Allan McGregor is confident of being fit after recovering from the groin strain that forced him off in the friendly win over Australia last month.
"He played on Saturday and kept a clean sheet," Houston added.
"We are absolutely delighted he's fully fit because his experience in playing big international matches is vital.
"We were convinced after the Australia game that he was struggling. He had a couple of injections and recovered brilliantly. Fair play to the (his club) for getting it sorted."