Yacob was forced to miss last weekend's defeat to Arsenal with a hamstring problem, while Ridgewell limped off with an ankle injury against the Gunners. Foster has missed the last six games following groin surgery, but it seems unlikely that he will be risked with Boaz Myhill set to continue. West Ham's injury worries have deepened ahead of their trip to the Hawthorns with defender George McCartney now a major doubt. McCartney injured a knee during training this week and is unlikely to feature. The setback is a fresh blow to Allardyce, who has also lost Mohamed Diame (hamstring) after he pulled up in last weekend's defeat to Liverpool. Yossi Benayoun, Andy Carroll and Jack Collison (all knee), Ricardo Vaz Te (shoulder) and Alou Diarra (thigh) are all missing for the Hammers.