Klopp said: "He is out. It's muscle this time – more serious than last time. We don't have a timeframe."
"It's a concern, how you can imagine," added the Liverpool boss. "It's not the first time we are in a situation like this. Last year, one game Fabinho played at centre-half. Unfortunately he is out as well. It's not too cool.
"In the moment we have two – we should take care of them, pack them in cotton wool and ask them what they want to do in training. Apart from that, we have to be creative; we have the kids, of course, with Ki-Jana [Hoever] and Sepp [van den Berg].
"We have defensive-minded midfielders, there are different systems where you can use different kind of defenders as well. That's how it is. In the moment, I have a lot of ideas but I hope for most of them I never have to use them, to be honest."