Manager Frank Lampard’s side start the 2020-21 season away against the Seagulls, with attacking midfielder Ziyech and left-back Chilwell set to miss the game.
Chelsea head coach Frank Lampard says new signings Hakim Ziyech and Ben Chilwell won’t be available for their Premier League game against Brighton on Monday.
The Blues boss also confirmed Brazil defender Thiago Silva, who moved to Stamford Bridge from PSG is unlikely to feature in the match at the Amex stadium.
The centre-back Silva is not yet training with the Blues first team, so he isn’t fit to start in the English top-flight.
"Hakim Ziyech took an injury to a knee against Brighton so won't be fit. Hopefully it's a matter of weeks, a couple of weeks but we have to see," Lampard said at Thursday's press conference.
"Ben Chilwell is working towards fitness and improved this week. He's going in the right direction but won't be ready for Brighton.
"Thiago is in London but not training with us until the weekend, so I doubt he's in contention for the game."
Chelsea have spent more than £200m on player recruits this summer, showing their ambition to win the Premier League title.