The Blues host the Saints at Stamford Bridge, looking to build on their 4-0 victory over Crystal Palace before the international break.
Eduoard Mendy, who arrived at the club from Rennes this summer, started the match ahead of Willy Caballero and Kepa Arrizabalaga.
Lampard has ruled out Mendy from the game, after he picked up a knock while on international duty with Senegal.
Thiago Silva has been ruled out, having arrived late from Brazil. Christian Pulisic is fit to start, while Ziyech might be on the bench.
“Mendy won’t be fit for the match tomorrow. We hope it won’t be long.
“Thiago Silva won’t be in the squad because of the travel. Ben Chilwell will be in the squad.
“Pulisic fit. Ziyech fit, but not to start. Ziyech looks good with his fitness in training and I am excited to get him in and around it to get him doing what we brought him to the club for,” Lampard said.