It doesn’t take a football genius to work out Liverpool’s big problem under Jurgen Klopp - they just aren’t very good defensively.The Reds have conceded 33 goals in their 26 matches in the league this season. To put that into context, that’s five more than 17th placed Middlesbrough.While Liverpool have scored the joint most in the division, you simply can’t expect their attackers to score three of four goals every match in order to win.On Monday against Leicester, it was Lucas Leiva and Joel Matip in the firing line as a Jamie Vardy brace and a Danny Drinkwater strike consigned them to a 3-1 defeat.In fairness, Dejan Lovren would probably be getting the nod alongside Matip but he’s struggling with an injury at the moment.But injuries is something that Klopp has had to deal with in defence since he’s been at Liverpool. In fact, injuries in that position got so desperate last season that the German signed Steven Caulker on loan as emergency cover.And now, the Times have discovered that Klopp has used 20 different centre-back partnerships since taking over in October 2015.If you can name all of them, then hats off to you.

As you can see, Lovren and Mamadou Sakho are the most used partnership having played together 14 times last season.

However, after Klopp fell out with Sakho before eventually allowing him to join Crystal Palace on loan, the Frenchman couldn’t continue his partnership with Lovren - where they held a 50% win percentage.

This season, when both fit, Lovren and Matip have been Klopp’s preferred choice but they’ve only played together 12 times. They also have a 50% win percentage and have only lost once when they’ve both started.

It’s something that Klopp certainly isn’t used to compared to his days at Borussia Dortmund. Klopp was able to call upon Mats Hummels and Neven Subotic consistently as he took the German club to the Bundesliga title.

Of course, injuries certainly don’t help but are some of these names that appear in the list good enough for a side challenging for top four? Probably not.

Lucas has been an excellent servant for the club, he was run ragged by an out-of-form Jamie Vardy on Monday, while Lovren is still failing to convince many Liverpool fans since his £20 million move from Southampton.

The decision to outcast Sakho - arguably Liverpool’s best defender last season - will continue to be questioned.

But one thing is for sure, Klopp needs to strengthen in defence this summer bringing in a couple of top quality players - preferably some that aren’t injury prone.

And this list is concrete evidence of that.