JAMIE CARRAGHER believes Liverpool FC will be deprived of their best player after Lucas Leiva’s worst fears were realised yesterday.

Lucas will miss the rest of the season after injuring the anterior cruciate ligament in his left knee during Liverpool FC's 2-0 Carling Cup quarter-final win at Chelsea on Tuesday.

The Brazilian suffered the damage while attempting a challenge on Juan Mata and, after initially attempting to play on, left the field in some distress on a stretcher.

Lucas underwent a scan on Wednesday which confirmed an absence of at least six months, the 24-year-old now facing surgery and a long period of rehabilitation.

It is a devastating blow to both the player and the club, with the midfielder having emerged as an influential member of Kenny Dalglish’s midfield.

Lucas was in the best form of his Liverpool career, having been an integral part of the ongoing 11-game unbeaten run and producing arguably his best performance for the club in their 1-1 draw with Premier League leaders Manchester City last Sunday.

And Carragher admits Liverpool will now be without their best player for the remainder of the season.

“For the last 18 months, in my opinion, he has been our best player,” said the vice-captain.

“Luis Suarez has come in and done great things for the club but Lucas has been his equal in many ways.

“He has been as good as anyone in the team this season and there is no question that he will be a big miss.”