The striker has been ruled out of the Aviva Stadium clash with a knee injury and has returned to Stoke for treatment.
Paul McShane is also a doubt after he sat out training on Monday while Birmingham midfielder Keith Fahey is currently laid low with flu'.
In Walters' absence, in-form West Brom front man Shane Long could return to the starting line-up after being marginalised in recent fixtures, as could young wingers James McClean and Robbie Brady.
Assistant coach Marco Tardelli said: "Maybe it's possible he starts the first half, maybe.
"We know he is playing very well because we were there on Saturday and he played well. But also, the other players are playing very well.
"We will wait until Wednesday, but we can change some players as we want to understand these new players some more. We think they are good, but they must show us that they can stay with us."