Kai Havertz was ruled out of Chelsea’s Champions League tie against Rennes tonight after contracting coronavirus.
The summer signing will now self-isolate and undergo further tests.
Christian Pulisic is also out, but is expected to be back for the weekend.
The American forward is already back in training after tests showed the hamstring injury he picked up in the warm-up before the win against Burnley was only a minor issue.
Frank Lampard has confirmed he should be fit again for Sheffield United’s visit to Stamford Bridge on Saturday.
The Chelsea manager said: “He had a scan and it is a very minor injury to his hamstring. He is already outside training. He’s not fit tomorrow, but we’ll see after that.”
This is the second hamstring problem Pulisic has suffered in quick succession after missing the start of the season.
Lampard admits it is a situation Chelsea’s medical staff are having to monitor.
“Some players who play on the edge and have that speed can be more susceptible. It’s not a one fits all answer," he said.
“Last season we were looking at ways to manage him and be proactive. It’s something he experienced before in his career at Dortmund.
“All working on getting him as fit as possible because we know the talent he has.”
Chelsea XI: Mendy, James, Thiago Silva, Zouma, Chilwell, Kante, Jorginho, Mount, Ziyech, Abraham, Werner
Subs: Rudiger, Alonso, Christensen, Caballero, Tomori, Kovacic, Giroud, Hudson-Odoi, Azpilicueta, Emerson Palmieri, Ziger
Rennes XI: Gomis, Traore, Da Silva, Aguerd, Dalbert, Nzonzi, Gboho, Lea Siliki, Bourigeaud, Terrier, Guirassy
Subs: Salin, Nyamsi, Grenier, Doku, Del Castillo, Hunou, Bonet, Truffert, Assignon, Georginio Rutter, Ugochukwu, Omari
Referee: Felix Zwayer
