West Ham are set to be without boss Avram Grant and defender Tal Ben Haim for Saturday's crunch bottom-of-the-table clash with Stoke City.
The Israeli pair are expected to be absent at the Britannia Stadium so they can observe the Jewish holy day of Yom Kippur.
They are required to participate in 25 hours of fasting and prayer over the course of Friday and Saturday, during which time Grant's assistant Zeljko Petrovic is likely to take charge of team affairs.
Grant observed Yom Kippur prior to his first match as Chelsea manager three years ago before flying by helicopter to Old Trafford for the game against Manchester United.
On-loan Portsmouth defender Ben Haim made his league debut for the Hammers in last weekend's 3-1 home defeat to Chelsea, which left Grant's men still searching for their first point of the season.
The defender could be replaced in the squad on Saturday by fellow newcomer Winston Reid, who made his comeback from a torn buttock muscle in Tuesday afternoon's reserve team victory at Everton.