Chelsea midfielder Danny Drinkwater has suffered a calf injury and will not make his Blues debut until October.
The England international, 27, moved to Stamford Bridge from Leicester on transfer deadline day for £35m.
"He had a muscular problem in his calf. He needs time to recover," said manager Antonio Conte.
"I think it is very difficult to see him before the international break. It is a pity because he was starting to work and to improve his physical condition.
"Now we have to move all these situations. And in two, three weeks, four weeks, I don't know."
|Chelsea's fixtures in September|
|17: Premier League - Arsenal (a)|
|20: EFL Cup - Nottingham Forest (h)|
|23: Premier League - Stoke (a)|
|27: Champions League - Atletico Madrid (a)|
|30: Premier League - Manchester City (h)|