The Irish centre-half this week went under the knife after aggravating his long-standing shoulder problem in training and is facing three months on the sidelines.
Claude Davis and Jose Fonte will therefore keep their places at the back.
Winger Sean Scannell is still doubtful with a hamstring problem and full-back Lee Hills is suspended so boss Neil Warnock could name the same side which beat Watford 3-0 last weekend.
Strikers Victor Moses and Alan Lee were on target and should retain their spots with Freddie Sears on the bench.
Darren Ambrose scored for the sixth successive game against the Hornets, a feat never before achieved by a Palace midfielder.