Chelsea have been handed an untimely injury concern with Kai Havertz ahead of the second leg of their Champions League quarter-final with Real Madrid on Tuesday.
With Pierre-Emerick Aubameyang out of favour and David Datro Fofana not being considered for first-team starts just yet, Havertz remains the Blues' first-choice number nine under Frank Lampard.
The Germany international has never really settled into the role, scoring just nine goals in 40 appearances this season, and he was benched for Chelsea's first-leg beating at the Bernabeu on Wednesday.
Havertz came on as a substitute for the final 25 minutes of that encounter, and he would have been a candidate to return to the first XI for the return fixture in West London.
However, the ex-Bayer Leverkusen man was nowhere to be seen in Saturday's Premier League loss to Brighton, with Lampard revealing that he had sustained a knock to the knee in Madrid.
Lampard expressed optimism over Havertz's chances of being fit for the reunion with the European champions, but any uncertainty over his fitness is far from ideal, with Aubameyang not called up to the Blues' Champions League knockout squad.
"Kai has had a little issue with his knee, which he felt in Madrid on Wednesday night. He should be fine for Tuesday," Lampard told the media prior to his side's loss to Brighton.
Chelsea paid Leverkusen a whopping €80m (£71.5m) to bring Havertz to the Premier League in 2020, and the 23-year-old has since posted 32 goals and 15 assists in 132 matches for the Blues.
Without Havertz in the ranks, Chelsea boss Lampard fielded Raheem Sterling furthest forward for the visit of Brighton, with Christian Pulisic and Mykhaylo Mudryk bombing down the flanks.
Chelsea's frontline struggled to gel once again, but the Blues took the lead thanks to a deflected Conor Gallagher strike - Chelsea's first goal since Lampard's homecoming.
However, Danny Welbeck's header levelled the scores before half time, and a wonder strike from Julio Enciso sealed a warranted three points for the Seagulls in the second 45.
The likes of Thiago Silva and N'Golo Kante were also absent from the squad with Tuesday's game in mind, but Cesar Azpilicueta was able to make the bench after recovering from the serious head injury that he sustained against Southampton.
The Blues will be without both of Armando Broja and Kalidou Koulibaly against Los Blancos, though, with the latter missing for a "matter of weeks" with a hamstring injury.
Chelsea have now suffered three successive defeats since Lampard returned to the dugout as interim manager, and they remain 11th in the Premier League table with seven games to go - closer to the relegation zone than the Champions League spots.
Goals from Karim Benzema and Marco Asensio gave Real Madrid a 2-0 win in the first leg of their continental quarter-final in the Spanish capital.
