Mateo Kovacic will miss Chelsea's Champions League trip to Zenit after testing positive for Covid-19.
The Croatia midfielder had only returned to training with the Blues on Monday after a lengthy hamstring problem, but has now suffered a fresh setback.
N’Golo Kante (knee), Jorginho (back), Trevoh Chalobah (hamstring) and Ben Chilwell (knee) will also miss the game in Russia.
Provisional Chelsea squad: Mendy, Arrizabalaga, Christensen, Silva, Rudiger, Sarr, Azpilicueta, James, Alonso, Hudson-Odoi, Saul, Loftus-Cheek, Barkley, Mount, Havertz, Ziyech, Pulisic, Werner, Lukaku.