PREVIEW By North-west correspondent Alex Stevens

Jurgen Klopp is set to restore the big hitters for Liverpool’s first European semi-final in six years but Martin Skrtel is expected to once again be overlooked.

The big decisions for Klopp ahead of the trip to Villarreal for the first-leg of the Europa League last-four clash are who should partner Dejan Lovren at centre-back and the identity of his central midfielders.

Mamadou Sakho has been suspended for 30 days by Uefa after it opened disciplinary proceedings against him following a failed drugs test.

Kolo Toure, Lucas Leiva and Martin Skrtel are the three players in contention to start instead of Sakho at centre-back, with the experienced Slovakian appearing the most unlikely after playing just 135 minutes since December following a difficult recovery from a hamstring injury.

Skrtel had a wretched return as a second-half substitute in the 3-2 defeat at Southampton last month – Liverpool were 2-0 up when he replaced Lovren at the interval – although he had a more comfortable match in the 2-1 win at Bournemouth recently.

Lucas was on the bench for the 2-2 draw against Newcastle last Saturday, which suggested the veteran was being saved to start in Spain, either as the midfield anchorman or in a centre-back position in which he has looked very comfortable during a number of matches this season, including the League Cup final defeat to Manchester City.

If Lucas partners Lovren, Joe Allen will start in central midfield and given the chance to continue the excellent impression he has made in recent months.

In recent months, the Merseysiders have produced their most free-flowing football since the 2013/14 campaign that so nearly ended in the Premier League title, scoring 18 goals in their last five matches.

At the heart of the revival has been the imaginative interplay of Philippe Coutinho, Roberto Firmino and Adam Lallana, while Daniel Sturridge has struck in four consecutive league matches.

The attacking quartet are all expected to start for a team weakened by the unavailability of four players who would have expected to be in the line-up.

With Divock Origi, Jordan Henderson and Emre Can all out injured and facing uphill battles to play again this season, and Sakho out of contention, youngsters Cameron Brannagan, Sheyi Ojo and Pedro Chirivella have flown to Spain as part of the 20-man squad along with fit-again Christian Benteke.

Liverpool (possible): Mignolet; Clyne, Lucas, Lovren, Moreno; Allen, Milner; Lallana, Firmino, Coutinho; Sturridge.

In other Liverpool team news, the Merseysiders have been given a fitness update on another big-name attacker.