diff --git a/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/constants/parameters_definition.tsx b/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/constants/parameters_definition.tsx
index 1277568b71bbd..64888253ecab4 100644
--- a/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/constants/parameters_definition.tsx
+++ b/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/constants/parameters_definition.tsx
@@ -299,7 +299,6 @@ export const PARAMETERS_DEFINITION = {
       type: FIELD_TYPES.TEXT,
       label: nullValueLabel,
     },
-    schema: t.string,
   },
   null_value_ip: {
     fieldConfig: {
diff --git a/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/lib/mappings_validator.test.ts b/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/lib/mappings_validator.test.ts
index 5c9fa3fd05d8c..bb86c6277ffe5 100644
--- a/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/lib/mappings_validator.test.ts
+++ b/x-pack/legacy/plugins/index_management/public/app/components/mappings_editor/lib/mappings_validator.test.ts
@@ -220,7 +220,6 @@ describe('Properties validator', () => {
         coerce: 1234,
         coerce_shape: '',
         ignore_malformed: 0,
-        null_value: {},
         null_value_numeric: 'abc',
         null_value_boolean: [],
         copy_to: [],