Chelsea boss Thomas Tuchel says Romelu Lukaku isn't yet ready to start in the Premier League.
Lukaku has recovered from an ankle injury, but didn't get on the pitch in defeat at West Ham until the second-half on Saturday.
Tuchel explained: "There's such a high intensity in the matches.
"I know Romelu is pushing, that's the nature of the beast. But there's a big difference between being ready to train and being competitive. And then there's being ready for the Premier League.
"We have to build up slowly. And he has to be patient."