Alvaro Morata has been battling a back injury that has kept him out of action.
Under pressure Chelsea boss Antonio Conte has admitted he has no idea how much more action summer signing Alvaro Morata could miss, with the striker seemingly unable to shake off a recent back injury.
The Spanish striker has been ruled out of the Blues last five matches due to ongoing back pain, with Conte admitting the club's medical staff were baffled in how to treat him.
Speaking to reporters at Chelsea's Cobham training ground on Friday - ahead of Monday's clash with West Brom - Conte said: "Players like Morata, for us, are very important and have been missing for a long period of time. I don't know how long he will be out."
Speaking to the Evening Standard, he added: "We are struggling a lot to find a solution to solve the pain in his back. If you ask me whether he needs a day, a month or the rest of the season, I don't know. I don't know.
"For this reason, I'm a bit worried. You know very well the importance of the player."
His replacement up front could be new signing Olivier Giroud, who joined the Blues from London rivals Arsenal in a transfer deadline day merry-go round. The Frenchman could be in line to make his first start against West Brom, despite a shortage in match fitness.
He added: "Giroud has trained and will be in contention. We are talking a lot about bad results, but sometimes we forget we are facing a serious situation.