What has the manager said?
It was confirmed in December that Chelsea's transfer ban has been lifted, which means they will be able to sign players in the January window.
"I think you've got to be careful about being too reactionary," said Frank Lampard. "Just as much as people at the start of the season who were saying we've got all these young boys, this is going to be no problem, we don't need any players.
"I think at a club like Chelsea, there needs to be a balance. You have a strong squad which I believe we have but you have to look at can we strengthen.
"And there will time times going forward, whether it's January or next summer, of course we're going to look at an opportunity to strengthen because we want to improve."
What did Chelsea do in the summer?
Chelsea were under a transfer embargo in the summer, but they did complete a permanent deal for Mateo Kovacic from Real Madrid, which came as part of his loan agreement from the 2018/19 season. Christian Pulisic also finally arrived from Borussia Dortmund following his January signing.
As usual, numerous young players headed out on loan, but some big names also departed. Eden Hazard finally left for Real Madrid while Alvaro Morata joined Atletico Madrid on a permanent deal for £58.3m. David Luiz also joined Arsenal for £8m, while Danny Drinkwater and Ethan Amapdu went out on loan.
Who have they been linked with?
Nathan Ake, Bournemouth [Sky Sports News]; Fedor Chalov, CSKA Moscow [Sky Sports News]; Victor Osimhen, Lille [Sky Sports News]; Reinier Jesus, Flamengo [Daily Express]; Habib Diallo, Metz [The Sun]; Isco, Real Madrid [The Sun]; Jadon Sancho, Borussia Dortmund [The Sun On Sunday]; Vinicius Junior, Real Madrid [El Desmarque]; Samuel Chukwueze, Villarreal [El Desmarque]; Leon Bailey, Bayer Leverkusen [The Sun]; Ben Chilwell, Leicester City [The Sun]; Sander Berge, Genk [Verdens Gang]; Eberechi Eze, QPR [The Sun]; Jarrad Branthwaite, Carlisle [Daily Mail].
Who could depart?
Olivier Giroud, Inter Milan or Juventus [Daily Express]; Giroud, Borussia Dortmund [Bild]; Marcos Alonso, Inter Milan [CalcioMercato]; Emerson, Juventus [Calciomercato].
Analysis: What to expect this January
Sky Sports News' Kaveh Solhekol...
"Chelsea are on the lookout for a centre-half and Bournemouth's Nathan Ake - their former academy star - is very much on their hotlist. The Blues have a £40m buy-back clause but may face competition from Manchester City and Spurs.
"They are also on lookout for a striker and they like Fedor Chalov at CSKA. There has also been a lot of speculation on Jadon Sancho of Borussia Dortmund too - a player most clubs in Europe also want to sign."
How to follow the January transfer window with Sky Sports
Sky Sports will bring you the very latest news from the January transfer market with the return of three shows.
Start your day with Good Morning Transfers at 9am as our team of reporters bring you the latest news and insight. Transfer Talk then follows at midday delivering analysis of the biggest stories. Then join us at 7pm for the definitive round-up of the day's news with The Transfer Show.
Meanwhile, the Transfer Talk podcast will also be back at the turn of the year with more expert analysis from here and across the continent.
And as well as tuning into Sky Sports News, don't miss a thing with our dedicated Transfer Centre blog.