diff --git a/scheduler/scheduler_system.go b/scheduler/scheduler_system.go
index 5d0278eae655..325e7ae00a5d 100644
--- a/scheduler/scheduler_system.go
+++ b/scheduler/scheduler_system.go
@@ -287,9 +287,16 @@ func mergeNodeFiltered(acc, curr *structs.AllocMetric) *structs.AllocMetric {
 
 	acc.NodesEvaluated += curr.NodesEvaluated
 	acc.NodesFiltered += curr.NodesFiltered
+
+	if acc.ClassFiltered == nil {
+		acc.ClassFiltered = make(map[string]int)
+	}
 	for k, v := range curr.ClassFiltered {
 		acc.ClassFiltered[k] += v
 	}
+	if acc.ConstraintFiltered == nil {
+		acc.ConstraintFiltered = make(map[string]int)
+	}
 	for k, v := range curr.ConstraintFiltered {
 		acc.ConstraintFiltered[k] += v
 	}