diff --git a/pkg/controller/statefulset/stateful_set_control.go b/pkg/controller/statefulset/stateful_set_control.go
index 01886d6895e..e8048ed2d91 100644
--- a/pkg/controller/statefulset/stateful_set_control.go
+++ b/pkg/controller/statefulset/stateful_set_control.go
@@ -566,8 +566,9 @@ func (ssc *defaultStatefulSetControl) updateStatefulSet(
 	}
 
 	// for any empty indices in the sequence [0,set.Spec.Replicas) create a new Pod at the correct revision
-	for ord := getStartOrdinal(set); ord <= getEndOrdinal(set); ord++ {
-		replicaIdx := ord - getStartOrdinal(set)
+	start, end := getStartOrdinal(set), getEndOrdinal(set)
+	for ord := start; ord <= end; ord++ {
+		replicaIdx := ord - start
 		if replicas[replicaIdx] == nil {
 			replicas[replicaIdx] = newVersionedStatefulSetPod(
 				currentSet,