diff --git a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/utils/StarTreeQueryHelper.java b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/utils/StarTreeQueryHelper.java
index e538be5d5bece..e46cf6f56b36e 100644
--- a/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/utils/StarTreeQueryHelper.java
+++ b/server/src/main/java/org/opensearch/index/compositeindex/datacube/startree/utils/StarTreeQueryHelper.java
@@ -152,7 +152,7 @@ private static MetricStat validateStarTreeMetricSupport(
             MetricStat metricStat = ((MetricAggregatorFactory) aggregatorFactory).getMetricStat();
             field = ((MetricAggregatorFactory) aggregatorFactory).getField();
 
-            if (supportedMetrics.containsKey(field) && supportedMetrics.get(field).contains(metricStat)) {
+            if (field != null && supportedMetrics.containsKey(field) && supportedMetrics.get(field).contains(metricStat)) {
                 return metricStat;
             }
         }
diff --git a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
index d862b2c2784de..41344fd06cbbc 100644
--- a/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
+++ b/server/src/main/java/org/opensearch/search/aggregations/support/ValuesSourceAggregatorFactory.java
@@ -104,6 +104,6 @@ public String getStatsSubtype() {
     }
 
     public String getField() {
-        return config.fieldContext().field();
+        return config.fieldContext() != null ? config.fieldContext().field() : null;
     }
 }