Chelsea could reportedly attempt to re-sign Nathan Ake from Bournemouth if head coach Frank Lampard decides that he needs a replacement for David Luiz.
Luiz left Stamford Bridge for Arsenal on transfer deadline day, while Antonio Rudiger's injury problems mean that the Blues have limited options in central defence heading into the 2019-20 campaign.
Chelsea are currently under a transfer suspension, which will also be in place for January as things stand.
However, according to The Telegraph, the London club could see the ban wiped out ahead of the winter window, which would allow them to improve their squad after a quiet summer.
The report claims that Ake has emerged as a potential target for the Blues, with the former Premier League champions learning that they can re-sign the Netherlands international for £40m.
The 24-year-old, who was also linked with Manchester City during the summer, made 17 first-team appearances for Chelsea during his time at the club before switching to Bournemouth, initially on loan.
Lampard's side, meanwhile, are also said to be eyeing an £80m swoop for Crystal Palace attacker Wilfried Zaha once their transfer ban is over.