Judging by Chelsea's form this season, it's hard to broadly look at the team and see any weaknesses. They've scored goals, they've got a decent goal difference, and, most importantly, they've won more than most.

However, whilst on the surface there may appear to be no flaws in the Chelsea team, it's clear that the defence is still a real worry for the Blues.

A notoriously solid outfit under Antonio Contee, the return to a four-man system has left the Blues looking vulnerable, and that was proven against the likes of Arsenal and Man City earlier this season.

Between Cesar Azpilicueta, Antonio Rudiger, David Luiz and Marcos Alonso, something just doesn't seem right about the Chelsea defence, and if Maurizio Sarri is going to win Chelsea the title this season, he'll need to improve the defence.

That will mostly come through work at Cobham, but there is also scope for further improvement at the back. In particular, David Luiz looks to be a particular weak point for the Blues, with his notoriously inconsistent style not corroborative with a solid defence.

Significantly, then, it has emerged this week, as per the Telegraph, that Chelsea have an option to land Nathan Ake from Bournemouth, an agreement made when he left London for the South Coast.

Ake, who is rated at £13.5 million by Transfer Markt, could be just the sort of player that Chelsea need.

Like Luiz, he's incredibly technical, and so he would fit the bill of the ball-playing defender that has become so popular in the modern era. More than comfortable with the ball at his feet, he's able to run with the ball and make attacks from the back, whilst he's also more than comfortable passing the ball to one of the players further ahead of him. Luiz has become known for his defence-splitting passes - and Ake is comfortable in this area too.

Unlike Luiz, though, he's a very solid defender, and mistakes have been few and far between over the years. Between his low-risk defensive style, well-timed tackling ability and his solid pace, he's always got the edge on attackers, and he's a natural when tracking back and looking to intercept play.

Ake is another example of a player that has left Chelsea and gone on to much greater things, and it would be a shame to see him move to a rival, as has been reported.

For the Blues, Ake could come in and add some real competition at the back, and though it could mean the end for Andreas Christensen, the Dane's poor form last season has raised question marks over his suitability. In Ake, Chelsea wouldn't have to worry about anything like that.

Chelsea fans - thoughts?

Let us know below!