And the German has detailed what they're seeking in any big money defensive signing.
Klopp accepts his team's attacking style of play makes it more difficult for centre-backs than at more defence-minded clubs.
“A centre-half for a top team is playing with a lot of space at the back," he says. “That's how Tottenham act, how City act and sometimes how Arsenal act. Manchester United are for sure a bit different.
“That is the situation, you have to involve a lot of players usually in offensive things, you cannot be offensive with two players in a counter-attack when there are already eight from the other team in their own half or box. So, yes, of course it is more difficult.
“If we go for a centre-half we need to know how he acts in big spaces, but on the other side centre-halves can feel pretty alone in certain moments if we don't react the right way after losing the ball.
“That is why counter-pressing is a pretty useful skill."
Klopp continued: "I saw a lot of centre-halves, that is how it is.
“We cannot go for a centre-half of Bayern Munich for example, they have similar problems that we have.
“You have to imagine how he will react in different situations. All clubs defend in some moments high.
“It is about being football-smart and they have make the right decision in the right moment, stepping back and all that stuff.
“For example, the second goal was after a set-piece, but it came after we lost the ball in build-up and things like this.
“If he steps back in this moment then for a few seconds there could be help from somewhere. It was two wrong decisions in one situation. That then is really difficult. But defending high is not a problem, it is only a different job."