Raheem Sterling has joined Chelsea's growing injury list after a knock in training and the England forward is a doubt for their Premier League London derby at West Ham United, manager Graham Potter said on Friday.

The 28-year-old is Chelsea's eighth player to be sidelined with injury, joining other forwards like Christian Pulisic and Armando Broja, and long-term absentees N'Golo Kante and Edouard Mendy.

Sterling has struggled to reproduce his Manchester City form following his 50 million pounds ($60.55 million) move to Chelsea, scoring only four goals in 16 league appearances.

"We've had a little setback with Raheem (Sterling) he had a little kick in training on the side of his knee, so we're assessing him and he is doubtful for tomorrow," Potter told reporters ahead of Saturday's game.

"Players are getting closer and closer. Wesley (Fofana) has been training with the team, Denis Zakaria has been training with the team.

"Mateo (Kovacic) has trained with the team but it's too soon for him. But we've got some options."

Potter will be boosted by the return of Joao Felix after the Portuguese forward served his three-match suspension following his red card on his Chelsea debut last month.

"We all saw the impact he had in his 60 minutes before the red card. You can see his quality, see it every day," Potter said.

"He's a player who can make a difference for us but we have to help him get integrated into the team, for him to understand what we're trying to do. But the signs are very positive."

Chelsea are looking to win their first away game in the league since October, a run of six matches which included three losses at Potter's former club Brighton & Hove Albion, Newcastle United and Fulham.

"It's not a statistic we like. Going away from home in the Premier League is not straightforward and the problems we've been having in terms of injuries haven't made it easy," Potter said.

"But it's something we're trying to address. We have to start with West Ham. I've been there with Brighton and had a decent record. But it's a different context, a London derby with no love lost between the two teams."

Potter also confirmed there was "nothing to report" on rumours of Pierre-Emerick Aubameyang seeking a loan move after the striker was left out of their Champions League squad.

"He is conducting himself well, a really good professional, and supporting his team mates," he added.

"While he is here, he's doing exactly what I expect him to do, which is to train well and act well."