LIVERPOOL FC will discover the extent of Lucas Leiva’s knee injury today amid fears the Brazilian could miss the rest of the season.

Lucas underwent a scan yesterday having suffered the damage during Liverpool FC’s 2-0 Carling Cup quarter-final win at Chelsea on Tuesday night.

The Brazilian injured himself while attempting to make a challenge on Juan Mata, eventually departing the field on a stretcher before hobbling away from Stamford Bridge on crutches.

Lucas had attempted to play on after receiving initial treatment, but was ultimately forced to admit defeat.

And privately the club and player are bracing themselves for the worst, with fears the 24-year-old may have damaged knee ligaments and be sidelined for up to six months.

That would realistically rule Lucas out for the remainder of the campaign, a devastating blow to the midfielder who has become one of Kenny Dalglish’s most influential and consistent performers and played an integral part in Liverpool’s ongoing 11-match unbeaten run.

Mindful of Lucas’s likely lengthy absence, Liverpool yesterday activated a release clause to summon midfielder Jonjo Shelvey back from his loan at Blackpool.

The 19-year-old enjoyed an impressive spell at the npower Championship side, scoring six goals in nine games including a hat-trick in a 5-0 victory at Leeds United.

Jamie Carragher, meanwhile, has set his sights on a first appearance at the new Wembley with Liverpool after Tuesday’s Stamford Bridge win.

The centre-back made his first appearance in a month to help Dalglish’s side reach the semi-finals of the Carling Cup for the first time since 2005.