“Russell won’t be available for the next two Saturdays,” Baggies boss Gary Megson told the clubs official website.
“It’s a vertebrae problem he’s had for quite a while. But it’s gone from being bearable where Russell could just get by to the point at Preston where it had gone too far.
“The prognosis isn’t very good. He had an epidural on Tuesday to hopefully ease his back problems.
"He could be out for nine months at best so it’s a case of fingers crossed.
"But if that doesn’t work we’ve got huge problems.