diff --git a/src/Plugin/search_api/processor/AddHierarchy.php b/src/Plugin/search_api/processor/AddHierarchy.php
index 2ef94a2..9783579 100644
--- a/src/Plugin/search_api/processor/AddHierarchy.php
+++ b/src/Plugin/search_api/processor/AddHierarchy.php
@@ -40,13 +40,6 @@ class AddHierarchy extends ProcessorPluginBase implements PluginFormInterface {
   protected $entityTypeManager;
 
   /**
-   * The fields helper.
-   *
-   * @var \Drupal\search_api\Utility\FieldsHelperInterface|null
-   */
-  protected static $fieldsHelper;
-
-  /**
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
@@ -60,26 +53,6 @@ class AddHierarchy extends ProcessorPluginBase implements PluginFormInterface {
   }
 
   /**
-   * Retrieves the fields helper.
-   *
-   * @return \Drupal\search_api\Utility\FieldsHelperInterface
-   *   The fields helper.
-   */
-  public static function getFieldsHelper() {
-    return static::$fieldsHelper ?: \Drupal::service('search_api.fields_helper');
-  }
-
-  /**
-   * Sets the fields helper.
-   *
-   * @param \Drupal\search_api\Utility\FieldsHelperInterface $fields_helper
-   *   The new fields helper.
-   */
-  public static function setFieldsHelper(FieldsHelperInterface $fields_helper) {
-    static::$fieldsHelper = $fields_helper;
-  }
-
-  /**
    * Retrieves the entity type manager service.
    *
    * @return \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
diff --git a/src/Processor/ProcessorPluginBase.php b/src/Processor/ProcessorPluginBase.php
index 947ae27..b7fcc68 100644
--- a/src/Processor/ProcessorPluginBase.php
+++ b/src/Processor/ProcessorPluginBase.php
@@ -51,7 +51,7 @@ abstract class ProcessorPluginBase extends IndexPluginBase implements ProcessorI
    *
    * @var \Drupal\search_api\Utility\FieldsHelperInterface|null
    */
-  protected $fieldsHelper;
+  protected static $fieldsHelper;
 
   /**
    * {@inheritdoc}
@@ -60,7 +60,7 @@ abstract class ProcessorPluginBase extends IndexPluginBase implements ProcessorI
     /** @var static $processor */
     $processor = parent::create($container, $configuration, $plugin_id, $plugin_definition);
 
-    $processor->setFieldsHelper($container->get('search_api.fields_helper'));
+    static::setFieldsHelper($container->get('search_api.fields_helper'));
 
     return $processor;
   }
@@ -71,8 +71,8 @@ abstract class ProcessorPluginBase extends IndexPluginBase implements ProcessorI
    * @return \Drupal\search_api\Utility\FieldsHelperInterface
    *   The fields helper.
    */
-  public function getFieldsHelper() {
-    return $this->fieldsHelper ?: \Drupal::service('search_api.fields_helper');
+  public static function getFieldsHelper() {
+    return static::$fieldsHelper ?: \Drupal::service('search_api.fields_helper');
   }
 
   /**
@@ -83,9 +83,8 @@ abstract class ProcessorPluginBase extends IndexPluginBase implements ProcessorI
    *
    * @return $this
    */
-  public function setFieldsHelper(FieldsHelperInterface $fields_helper) {
-    $this->fieldsHelper = $fields_helper;
-    return $this;
+  public static function setFieldsHelper(FieldsHelperInterface $fields_helper) {
+    static::$fieldsHelper = $fields_helper;
   }
 
   /**