"It's a knee issue in this moment. Until we have the scan we hope for everything, but it doesn't look too good. I don't want to speculate [on what it is] because what can I say until we have the scan? It is not a small thing, I think, that's what we can say."
Liverpool's captain spoke in the week about how he has been playing with the same heel injury that kept him out earlier on in the season, as reported by Sky Sports:
"Sometimes I can be my own worst enemy if I'm playing with an injury or different things. It's my own fault at times, but that's just the way I am.When it completely goes will be whenever I have a rest, but I'm not sure if I'll have one any time soon."
There is a distinct possibility he may have been subconsciously compensating for the pain in his heel, which has subsequently contributed to his knee injury.
Liverpool have been cursed by injuries since Klopp's arrival earlier on in the season, with the likes of Daniel Sturridge, Philippe Coutinho and Martin Škrtel having faced lengthy spells on the sidelines.
The injury to their captain will be a blow for Liverpool after his return to form of late. He had received much criticism earlier on in the season, but has bounced back with a string of powerful midfield displays.
Liverpool face Stoke City at Anfield on Sunday, where a win would see the Reds leapfrog the Potters in the table.