Queens Park Rangers manager Harry Redknapp has described Sandro's knee injury as a "big blow" to the club's season.
The Brazilian is not expected to play again until the New Year after suffering ligament damage during QPR's 1-0 defeat to Newcastle United last weekend.
"Losing Sandro until after Christmas is a big blow," Redknapp told reporters. "He took a bad bang to his knee, but it could have been worse."
QPR are currently at the bottom of the Premier League table, three points away from safety.