Since his arrival at Anfield in October 2015, Jurgen Klopp boasts a strong record against big clubs -- and a particularly impressive record against this weekend's opponents, Chelsea. Two draws at Anfield and two fine victories at Stamford Bridge represents an excellent return of eight points from four matches.

This weekend, Liverpool face a Chelsea side attempting a slightly different strategy. Whereas previously their outstanding attacker, Eden Hazard, was fielded on the left of a 4-3-3 or 3-4-3 system, this weekend he's likely to start centrally, fielded just behind Alvaro Morata, and allowed license to drift laterally across the pitch into pockets of space.

This might prove particularly problematic for Liverpool, because it's in precisely that zone -- between the lines, in front of their own defence -- that Klopp's side have been regularly exposed in recent weeks. The problem, by common consent, is Jordan Henderson.

It was against Chelsea last season, in the superb 2-1 victory at Stamford Bridge on Sept. 16, that Henderson initially outlined his ability to play the holding midfield role, having previously been considered a more attacking player. He scored an outstanding, long-range curler into the top corner, but his overall performance was fantastic. He found space, controlled possession and thwarted counter-attacks. He subsequently enjoyed a good campaign for Liverpool, and yet in the opening months of this campaign has regularly been hugely underwhelming. So what's changed?

The short answer is simple: Liverpool have. When Klopp joined, he immediately installed aggressive counter-pressing as his main approach. From his opening match against Tottenham, his players were evidently on board, charging around to pressure Spurs players, with Klopp overtly cheering any successful spells of pressing from the touchline. The possession play and attacking combinations came later. Liverpool were, first and foremost, about pressing.

Since then, Liverpool have pressed less and less and this neat visualisation outlines the story excellently. In 2015-16, Liverpool won possession in very advanced positions, the following season they took more of a medium block, and now they're disrupting the opposition in much deeper positions. They are no longer such a pressing side.

That final chart could be misleading -- it suggests that Liverpool are adept at regaining possession in that zone Henderson is patrolling. It is a rather more complex situation, of course -- Liverpool are allowing the opposition to advance closer to goal, and while a decent number of attacks are broken up in that zone, there's also a fair number which aren't. And this is where Henderson's role has changed completely -- he's still playing holding midfield, but whereas previously his job was about chasing and harrying, now it's about sitting and protecting.

Jordan Henderson excelled against Chelsea last season but his and Liverpool's fortunes have wavered since then. AP Photo/Frank Augstein

This doesn't come naturally to Henderson and is another new role he's been forced to learn. Often deployed as a right-sided midfielder in his first Liverpool campaign under Kenny Dalglish, he first impressed under Brendan Rodgers when deployed as an energetic, box-to-box midfielder, or even at the head of a midfield triangle where his energy helped Liverpool start the press.

When suspended, he was a crucial loss from Liverpool's infamous, title-losing 2-0 defeat to Chelsea in April 2014 because Liverpool desperately missed his forward running and it's hardly surprising he's not particularly comfortable sitting in front of his own defence, playing the Claude Makelele role.

Henderson is fundamentally a runner who covers lots of ground, and his periods of good form -- whether as an advanced midfielder, a box-to-box midfielder or a defensive midfielder in a pressing side -- have enabled him to showcase his energy.

Moreover, he isn't simply playing in a zone largely unfamiliar to him, he's playing behind five hugely attack-minded players. The redeployment of Philippe Coutinho in a midfield role makes sense considering the Brazilian's skillset, but he's not good at recovering his defensive position. Georginio Wijnaldum is another naturally creative player, to the extent he was deployed as a No. 10 by Rafael Benitez at Newcastle.

With Sadio Mane and Mohamed Salah granted more freedom to remain in attack-minded positions than Klopp allowed his wingers last season, Henderson is often simply overwhelmed, forced to cover too much space. He often compounds this problem by making the wrong decision, tempted to shut down one opponent, becoming dragged away from the centre and allowing another to exploit that crucial zone between the lines.

Liverpool vs. Chelsea is the game of the weekend in the Premier League. Football Whispers

One incident, from the first half of Liverpool's 3-3 draw with Sevilla in midweek, summarised the problem. With Liverpool 1-0 up, Salah conceded possession with a wayward crossfield pass and Liverpool were in a poor shape to defend the counter, with five men ahead of the ball. Just Henderson and the back four remain intact.

Henderson checks over his shoulder to make sure Sevilla's striker is being marked -- he is -- so takes his cue to move towards the player starting the counter-attack from Liverpool's right, Ever Banega. But in moving towards Banega, he leaves his position completely bare for Pablo Sarabia.

Banega plays the ball to Sarabia between the lines, which forces Liverpool left-back Alberto Moreno to sprint inside into a position in front of his defence. In turn, this means Sevilla centre-forward Wissam ben Yedder spots Liverpool's vacant left-back space and peels off on to the outside. Eventually, Sarabia plays a through-ball from the hole, to Ben Yedder in Moreno's vacant zone and, in a one-on-one chance, he pulls the ball narrowly wide.

That single moment summarises Liverpool's defensive problems. Initially you think it's the fault of Moreno, wildly out of position. Then you realise Moreno has been dragged inside because Henderson has been closing down elsewhere. Then you realise Henderson has been closing down after being exposed at a turnover of possession because Liverpool have lost too many men ahead of the ball.

Moreno and Henderson are the fall guys, but overall Liverpool's defensive problems in open play stem from the lack of cohesion, with Klopp's side no longer pressing cohesively, but not yet getting back into a solid unit behind the ball either. Caught between two stools, Henderson has been unfairly cast as Liverpool's problem, when realistically he's merely a symbol of their issues.