The defender suffered a muscular injury during Sunday's FA Cup semi-final victory over Tottenham Hotspur.
As a result, Di Matteo expects to be without the Brazilian for at least two weeks.
"David Luiz is a big loss," Di Matteo told reporters. "We hope to get him back in two weeks and hopefully he can be ready for the end of the season."
Gary Cahill is expected to start at Stamford Bridge in Luiz's absence.