From the moment that he took the job at Stamford Bridge, Maurizio Sarri has been keen to strengthen defensively.
Sarri chased the signature of Daniele Rugani throughout the summer, but his pursuit was unsuccessful.
However, he remains keen to add to his options following reports that Gary Cahill is set to leave the club.
With concerns over the long-term futures of David Luiz and Andreas Christensen, he may be in the market for a defender sooner rather than later.
We’ve looked at some options Sarri could consider to freshen things up at the back.
Jose Gimenez
Gimenez is very highly rated in Spain, so convincing Atletico to sell may be a challenge in itself.
However, it will not be long before big European clubs come calling for Gimenez and the wages that Chelsea could offer would far eclipse what he is earning at Atletico Madrid.
Medhi Benatia
Medhi Benatia has drawn a lot of links to the Premier League in recent weeks.
The Morrocan looks set to leave Juventus in the near future after falling out of favour.
However, he remains a very capable defender. He was a key part of their success last season but has suffered as a result of Leonardo Bonucci’s return.
Daniele Rugani
If Benatia is not the one for them, but they fancy another Juventus defender then they could turn to Daniele Rugani.
The Italian is also out of favour and was heavily linked with Chelsea over the summer.
Rugani is being linked with the likes of Milan, while Chelsea are also still believed to be interested.
Whether or not he would be a major upgrade is still yet to be seen.
Gianluca Mancini
Gianluca Mancini appears to be part of the next generation of Italian defenders.
His performances for Atalanta are earning rave reviews across Europe and Arsenal have recently been linked with the player.
Expect interest in him to rise in the not too distant future.
Jonathan Tah
The Bayer Leverkusen defender has long been tipped for big things in Europe.
It will not be long before your Dortmund’s and Bayern’s are being linked with big-money moves to sign the German international.
Chelsea could be an option if Dortmund and Bayern decide against poaching one of the better defensive talents in the Bundesliga.
Issa Diop
An option that is a little closer to home is West Ham’s Issa Diop.
Manchester United and PSG have already been linked with the player after a fine start to the season in London.
His pace, power and awareness make him an ideal defender for the Premier League. West Ham will face a battle to keep hold of him if he continues his current form.
Matthias Ginter
The 24-year-old is living up to his potential at Gladbach and impressed plenty in the Bundesliga last season.
Should he continue to impress in Germany, he is likely to attract a wealth of interest going forward.
Benjamin Pavard
Benjamin Pavard was a player that was heavily linked with a number of moves over the summer.
The versatile defender was wanted by both Arsenal and Bayern after his exploits for France in Russia, but he remained with Stuttgart.
Reports have suggested there could an agreement in place already to join Bayern, which could be a difficult factor other potential suitors.