It is a groin injury that has kept the 23-year-old Cole Palmer away from play for almost a month. Chelsea's coach Enzo Maresca had hoped that Palmer would be back after the international break.
I was wrong. Unfortunately, he will probably be out for six weeks, says Maresca.
According to Maresca, no surgery is needed.
We are trying to protect Cole as much as we can. Most importantly, he is fully restored when he comes back, he says.
Chelsea meet Nottingham in the Premier League on Saturday.