Chelsea boss Hiddink admits Ferreira out for season
Ferreira, 30, is the third Blues player to suffer the knee problem this season following Joe Cole and Michael Essien.
But, on the plus side, midfielder Essien is fit again and in today's squad, along with defender Ricardo Carvalho.
Hiddink said: "Paulo got injured yesterday and has anterior ligament damage. It means he is out for the season.
"But Essien and Carvalho both travel. I am happy to have two more players with international experience back in the squad.
"We want to get into the semi-finals of the FA Cup - the competition is highly regarded at home and abroad. But I have no priorities about the next two games.
"The next step after Coventry is very important against Juve. But I have not got any specific priorities."