Jurgen Klopp Liverpool FC
Jurgen Klopp's Liverpool have qualified for Europa League's knockout stage FRANCK FIFE/AFP News

Liverpool boss Jurgen Klopp has opened up on midfielder Alexis Mac Allister's "tricky" injury that will keep him out of their big game against Manchester United.

Klopp said that he had never experienced an injury like Mac Allister's before, and Liverpool handled the situation with utmost caution. The Argentinian midfielder was forced off with a knee injury during Liverpool's 2-0 win at Sheffield United last week.

Mac Allister subsequently missed the Reds' Premier League clash against Crystal Palace and has not travelled for their Europa League clash against Union Saint-Gilloise on Thursday.

Klopp: Mac Allister's injury is tricky

Speaking in a pre-match conference on Wednesday, Klopp confirmed that the former Brighton midfielder's injury was painful but did not reveal if it was a long-term injury.

"I am obviously not a doctor but they explain it to me pretty much every day why he is not ready yet and it is a bit more tricky than we thought in the first moment.

"The other boy stepped on his knee and the stud went through pretty much the muscle onto the bone. And now we have to wait until the bone is healed and until Macca can deal with the pain, because it is pretty painful," Klopp told reporters.

Klopp added that Mac Allister is a "super tough guy" and Liverpool only need to ensure that the World Cup winner does not catch any infection. "I've never had this injury in one of my players before but hopefully, in the next three or four days he makes big steps," the German boss said.

Joel Matip undergoes surgery

Liverpool are already without the services of centre-back Joel Matip, who sustained a season-ending ACL injury during the Reds' 4-3 victory over Fulham in the Premier League on Dec. 3. He was forced off the field at Anfield in the second half of the game and scans later confirmed an ACL injury.

The star defender has now successfully undergone surgery but is set to miss the remainder of the 2023-24 campaign. He will continue his rehabilitation programme at the AXA Training Centre. Before picking up the ACL injury, Matip had made 14 appearances in 2023-24 season – his eighth season with the club – and passed the 200 mark overall for Liverpool.

Klopp and Co have not given a timescale on Maptip's recovery. The defender's current contract with Liverpool is due to expire at the end of the season. It could very well be assumed that the outing against Fulham may have been Matip's final appearance for Liverpool.

The Anfield side has travelled to Brussels for their final group game of the Europa League, against Union Saint-Gilloise. Having already qualified for the knockout stage of the competition, Klopp decided to leave behind several star players like Mohamed Salah, Trent Alexander-Arnold and Virgil van Dijk.

The group winners in the Europa League receive a straight qualification for the last-16 stage and avoid an extra round in which the runners-up face off against the Champions League drop-outs. Now that Liverpool have qualified for the knock-out stage, they don't have to think about Thursday night European football until early March.

Liverpool are at the top of the 2023-24 Premier League table with 37 points in 16 games, one point clear of second-placed Arsenal and two points ahead of third-placed Manchester City.

The Reds' star forward, Salah, is the second leading goal scorer in the league this season. He has netted 11 goals and is just three goals behind City's Erling Haaland in the Golden Boot race.

Liverpool have a very busy December lined up. Following their Europa League game, they next take on arch-rivals Manchester United in a crucial Premier League game at Anfield on Sunday. Two days later, the Reds will take on West Ham in the League Cup quarter-final.