Kelly, 32, was taken off at the end of the first half of the 4-2 loss at the Hawthorns.
It was initially feared that he had broken a bone in his foot but scans have revealed considerable bruising but no fractures.
With the Coca-Cola Championship on a week off due to the international break, Kelly could even return to action in time for the Whites' next league outing against Stoke City on Saturday week.