The Brazil international was carried off on a stretcher in the second half of the Reds' 2-0 League Cup quarter-final win at Chelsea on Tuesday.

　　Manager Kenny Dalglish's worst fears were confirmed after a scan revealed damage to the anterior cruciate ligament in the player's left knee.

　　"The Brazil international will undergo surgery and unfortunately be ruled out for the remainder of the current campaign," said a statement from the club.

　　News of Lucas' injury is a crushing blow to Dalglish and the rest of the team as the 24-year-old has been one of Liverpool's best players over the last two seasons.

　　In the last fortnight, in particular, the Brazilian has shown his worth with impressive performances against Chelsea in both the Barclays Premier League and Carling Cup victories and also in the 1-1 draw at home to Manchester City on Sunday.

　　He has forged a successful central midfield partnership with summer signing Charlie Adam, under-taking the defensive anchor role to allow the Scotland international to play a more expansive game.

　　Liverpool obviously feared the worst after an initial assessment on Lucas following his clash with Chelsea's Juan Mata as yesterday they recalled midfielder Jonjo Shelvey from his loan spell at npower Championship side Blackpool.

　　Dalglish still has plenty of options in midfield with Jay Spearing having the attributes most similar to Lucas in terms of defensive duties.

　　Another summer signing Jordan Henderson could well move back inside, having spent most of his short Reds career struggling out on the right, and while Shelvey has been in great form for the Seasiders, scoring six times in 10 matches, he is likely to be a back-up.

　　The ideal scenario for Dalglish would be a swift return for captain Steven Gerrard.

　　He has made just five appearances this season, having had a delayed start after recovering from a groin operation in April, and has not played since October 22 because of an ankle infection.