Tuchel said this during his pre-match press conference on Friday ahead of the Man City clash.
Chalobah, James and Chilwell are all injured, while Christensen battles COVID-19.
“No news, which is good news. Trevoh will be out, Reece James out, Ben Chilwell out,” Tuchel said.
“We have one new positive Covid test with Andreas Christensen, so he will be out of the game,” he added.
Chelsea head to the game after beating Tottenham Hotspur 1-0 in the EFL Cup semi-final second leg encounter on Wednesday.
The Blues are currently in the second position on the Premier League table with 10 points behind leaders Man City.
The kick-off time for Man City vs Chelsea is 1.30 pm.