Luis Garcia will have a scan on Wednesday morning to determine the extent of the knee injury he sustained in the Carling Cup defeat to Arsenal.
Garcia was stretchered off during the second half and manager Rafael Benitez fears the Spaniard could be out of action for some time.
He said: "Luis has a knee problem but at this moment we don't have news. He will have a scan tomorrow but it looks like we could be without him for a long time."
Mark Gonzalez (shin) and Stephen Warnock (bruised ribs) also left the field injured during the game but neither player is thought to be facing a lengthy spell on the sidelines.
Stay tuned to Liverpoolfc.tv for the up to date injury news on Wednesday.
Benitez, meanwhile, was left to reflect on Liverpool's second Cup defeat to Arsenal in the space of four days as Arsene Wenger's men ran out 6-3 winners.
He said: "It's a bad night for us and all we can say is sorry to the supporters.
"Now isn't the time to point the finger or look to blame people. We win together and we lose together.
"The problem was conceding four goals in the first half. When you are faced with a scoreline like that it is very difficult to manage the game.
"We needed an early goal in the second half but couldn't find it. When we did score Arsenal had the quality to keep the ball and make it difficult for us.
"We need to forget about tonight as soon as possible and look ahead to Watford in the Premiership on Saturday and also the Champions League."
Just what we needed after tonight. A player who [like him or not] has made a contribution in every season with his goals.
Not only that but Gonzalez is injured and it means less players available to play on the left-hand side. I really don't want to see Riise there but it seems that he will play there with Aurelio or Warnock at left-back.
[Signing Lucas Neil doesn't sound all that bad now does it
