Real Madrid coach Fabio Capello fears both David Beckham and Jose Antonio Reyes could face lengthy spells on the sidelines.
Beckham hobbled out of Real's 1-1 draw with Getafe after crashing into advertising hoardings in the second half.
Reyes was stretchered off, again with a knee injury - and the pair are now out of Real's UEFA Champions League second leg clash with Bayern Munich on Wednesday.
Capello is now waiting on the results of scans, before he can be sure how long the pair will be out for - although it seems highly unlikely that either will feature in the Gran Clasico against arch-rivals Barcelona next weekend.
"Neither of them will play in Germany," said Capello.
"One of the injuries is serious and the other could be something important.
"We will have to see."
The injury for Beckham also seems to rule out the prospect of an England recall for the ex-captain - who has not featured for his country since last summer's World Cup finals.