Sandro was left behind by Tottenham as they flew out to Germany on Monday.
The Daily Mail says Sandro was left in the departure lounge at Stansted airport on Monday after a communication breakdown meant he failed to realise he is not in the squad for the Champions League.
However, Sandro, 21, has not been included on Tottenham's 'A' list for the competition and would need to have been with the club for two years to make list 'B'.
Manager Harry Redknapp and club secretary Darren Eales told a shocked and disappointed Sandro he would not be boarding the plane for tonight's Group A opener in Bremen.
He will, instead, play in a behind-closed-doors friendly on Wednesday.