Pienaar adds to Spurs injury woes
Pienaar has been struggling with a groin injury for several weeks, and although he played for South Africa during the recent international break, he revealed on his Twitter account that the injury had flared up again.
"Out for the Madrid game. Groin still not right," he wrote.
Spurs are already without central defenders Ledley King, Jonathan Woodgate and Younes Kaboul.
Right-back Alan Hutton needs surgery on a knee injury which will keep him out for the season, while manager Harry Redknapp has doubts over the fitness of William Gallas and Tom Huddlestone, although Gareth Bale should be fit.