McCartney injured a knee during training this week and is unlikely to feature at the Hawthorns.
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.
- Sports & Recreation
- Ricardo Vaz Te
- Andy Carroll