Spain defender Carles Puyol could miss their Euro 2004 Group A showdown with Portugal in Lisbon next Sunday.
Puyol's knee was heavily strapped after picking up a knock against Greece.
"It is very sore and it feels bad," he said. "I can't say if I'll be fit by the weekend, it's a bit too early but it feels bad right now."
Spain will already be without centre-back Carlos Marchena, who is suspended after collecting his second yellow card of the tournament against Greece.