Head coach Mauricio Pochettino says that he hopes that the knee injury sustained by Chelsea forward Christopher Nkunku against Borussia Dortmund on Wednesday night is "nothing big".
Chelsea have enjoyed a productive pre-season tour of the United States, winning the Premier League Summer Series through collecting seven points from games with Brighton & Hove Albion, Newcastle United and Fulham.
That run followed a 5-0 win over Wrexham, with the Blues completing their schedule against Dortmund - last-16 opponents from the 2022-23 Champions League - at Soldier Field in Chicago.
The game itself ended in a 1-1 draw, young Chelsea striker Mason Burstow netting an 89th-minute equaliser after Marius Wolf had given Dortmund the lead nine minutes earlier.
However, Chelsea's main concern is the condition of Nkunku, who lasted just 22 minutes after being forced off with a knee problem in the first half.
The summer signing, who has arrived from RB Leipzig, was able to walk off the pitch unaided, and he was later seen with an ice pack on the injured area.
Nevertheless, Chelsea's medical staff will not assess Nkunku until the squad arrive back in London over the next 24 hours.
After the game, Pochettino said, as quoted by the club's official website: "The doctors are checking him and I hope it is not a big issue.
"He fell in the action which was maybe a penalty and he feels something in his knee but we hope it is nothing big.
"We hope he can be back quickly with the team. We need a few days to assess him."
When fit, Nkunku is regarded as a certain starter by Pochettino, the France international having accumulated 244 minutes of action across four friendlies before the meeting with Dortmund.
During that period, Nkunku has scored three goals, and Chelsea will hope that he can still be available for their Premier League opener against Liverpool on August 13.
In his place, Mykhaylo Mudryk was able to come through 69 minutes, his most game time of the summer thus far, and the Ukraine international supplied the free kick which eventually led to Burstow's coolly-taken header in the closing stages.
