Israeli Grant will observe Yom Kippur, also known as the Day of Atonement, which is the most important in the Jewish religious calendar and Hammers co-owner David Sullivan is hugely sympathetic to his manager's religious predicament.
''In the world we live in one has to respect somebody's religion,'' Sullivan told ESPNsoccernet. 'Sadly the Day of Atonement falls on a Saturday one year in seven and sadly for us it's this year.'
Zeljko Petrovic, West Ham's assistant manager, is not believed to be favoured to take over the role in Grant's absence, and Groves is primed to take control, perhaps given his experience of managing Grimsby in over 100 games.
Tal Ben Haim, the Israeli international defender, also will be missing from the Hammers squad and it couldn't come at a worse time for the Hammers as they are rooted at the bottom of the table with no points.
Grant has always observed Yom Kippur in the past. In 2007, only 36 hours after being appointed Chelsea manager, he observed Yom Kippur even though it was the day before a vital away match at Manchester United.
According to the Jewish Chronicle, Avi Cohen, the first ever Israeli to play in England, caused a storm in Israel when he turned out for Liverpool in a match against Southampton on Yom Kippur in 1980.
Avi Cohen's son Tamir currently plays for Bolton, who are away to Aston Villa on Yom Kippur, although he has not appeared for the first team this season. Chelsea's Yossi Benayoun and Blackpool's Dekel Keinan play at Stamford Bridge in a Sunday game, and are therefore unaffected." (source)
