Chelsea have made a very solid start to the season, sitting comfortably inside the top four.

Frank Lampard's faith in youth was essential after a transfer ban meant they couldn't do any business in the summer window.

However, that ban was lifted and they are free to buy players in the January transfer window, hoping to bolster their squad as they get into the business end of both the Premier League and the Champions League.

Ahead of that window opening, here's three of their current squad who could be under pressure:

Willian

The Brazilian has been a regular for Lampard, making 21 appearances this season. However, the club have been linked with both Jadon Sancho and Wilfried Zaha since their ban was lifted, and they could slot into Willian's position in the starting lineup. The 31-year-old's contract expires in the summer, and with youngster Callum Hudson-Odoi and Christian Pulisic already competing for the two slots on the wings, it doesn't look like Willian has much of a future at Stamford Bridge.

Kurt Zouma

France international Zouma returned from a loan spell at Everton and went right back into the Chelsea first team. He's already made 24 appearances this season, but there have been some poor displays. His horror-show on the opening day against Manchester United earned him a rating of just 4.86 on WhoScored, while he was at the heart of the defence that collapsed in the 3-1 defeat to Everton. Antonio Rudiger has returned from injury and could replace Zouma in the team if such performances keep occurring, as could Nathan Ake - with the former Chelsea man linked with a return to the Bridge in the upcoming window.

Tammy Abraham

The England international has been very impressive since taking the number nine shirt at Stamford Bridge. He's scored 13 goals and registered five assists in his 23 appearances so far this season. However, the Blues have been linked with strikers in the transfer market.

Lyon's Moussa Dembele and RB Leipzig's Timo Werner are both reported targets for Lampard. If Abraham's goals start to dry up, Chelsea could very well make a serious play for either, which could make life more difficult for the 22-year-old at Stamford Bridge, even despite his phenomenal start to life as a top-flight centre-forward.