Liverpool's preparations for their Champions League quarter-final against Manchester City have been dealt a huge blow after a thigh injury ruled out Joel Matip for the rest of the season.
The centre-back sustained a problem in Saturday's win at Crystal Palace and will require an operation.
A statement on the club’s website read: "Matip was able to complete the full 90 minutes of the fixture, but afterwards medical assessment on the thigh revealed surgery is expected to be required to correct the problem.
"The operation is likely to end the 26-year-old's involvement in the remainder of the 2017-18 season."
Read more: Liverpool v Manchester City head to head analysis ahead of Champions League quarter-final
Speaking at his press conference, Klopp gave an update on Liverpool's other injured players ahead of Wednesday's first-leg clash at Anfield.
He said: "Joel (Matip) is out for the rest of the season, no doubt about that. It's very serious.
"Emre (Can) will at least be very close for tomorrow - but it doesn't look too good. Ragnar Klavan is unavailable. If there is a centre-half in the room I am open for talks!"
To qualify for the Champions League quarter-finals: Man City 4/9 Liverpool 13/8 with Sky Bet
The German also gave England fans hope that Adam Lallana could be available for the World Cup after suggesting there is a small chance he may play again this season.
The 29-year-old was forced off just five minutes after coming on as a substitute against Crystal Palace on Saturday but Klopp says his leg injury is not as bad as the Reds first feared.
He added on Liverpoolfc.com: "Thank God, that's not as bad as we thought - a number of weeks. There is a little hope, of course, that we can maybe use him again this season but we have to wait. It is absolutely not the time to bring any rush into the situation.
"It is not the Adam Lallana season so far. It makes the season so far even more special when you think that we have played the season without him. He will be back for pre-season, of course."
Liverpool are the only team to have beaten City in the Premier League so far this season but Klopp knows doing so is far from easy.
He said: "It is a big game against one of the best teams - if not the best team - in Europe. That's nice.
"We beat City a few months ago. We know it's possible. It's just unbelievably difficult to do it.
"I have never beaten Pep Guardiola - it was always my teams. The record is not important. Pep is not worried about that record and I am not."
All-time XIs - whose is better?
Footballers managed by Jurgen Klopp at Borussia Dortmund and Liverpool
Footballers managed by Pep Guardiola at Manchester City, Bayern Munich and Barcelona
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Last updated at 1545 BST 03/04/2018.