The Portugese international was subsituted after 20 minutes against Bolton on New Year's Day with an ankle injury. That knock has ruled him out of tonight's visit to Ewood Park but the Reds are hopeful he will be fit for Sunday's FA Cup game with Man Utd.
"He's got bone bruising on his ankle. This isn't as bad as we first thought," said Sammy Lee.
"Unfortunately he's not available for Blackburn but he's a tough cookie and hopefully he will be back for Sunday."