diff --git a/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java b/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java
index 135cb53f65f..8aa4897a8e0 100644
--- a/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java
+++ b/core/src/main/java/org/elasticsearch/common/lucene/search/function/FieldValueFactorFunction.java
@@ -161,9 +161,6 @@ public class FieldValueFactorFunction extends ScoreFunction {
 
         @Override
         public String toString() {
-            if (this == NONE) {
-                return "";
-            }
             return super.toString().toLowerCase(Locale.ROOT);
         }
     }