diff --git a/src/Utility/FieldsHelper.php b/src/Utility/FieldsHelper.php
index 33d9a293..819245fd 100644
--- a/src/Utility/FieldsHelper.php
+++ b/src/Utility/FieldsHelper.php
@@ -81,16 +81,21 @@ class FieldsHelper implements FieldsHelperInterface {
    *   The entity type bundle info service.
    * @param \Drupal\search_api\Utility\DataTypeHelperInterface $dataTypeHelper
    *   The data type helper service.
-   * @param \Drupal\search_api\Utility\ThemeSwitcherInterface $themeSwitcher
-   *   The theme switcher service.
+   * @param \Drupal\search_api\Utility\ThemeSwitcherInterface|null $themeSwitcher
+   *   (optional) The theme switcher service.
    */
   public function __construct(
     EntityTypeManagerInterface $entityTypeManager,
     EntityFieldManagerInterface $entityFieldManager,
     EntityTypeBundleInfoInterface $entityBundleInfo,
     DataTypeHelperInterface $dataTypeHelper,
-    ThemeSwitcherInterface $themeSwitcher
+    ?ThemeSwitcherInterface $themeSwitcher = NULL,
   ) {
+    if (!$themeSwitcher) {
+      @trigger_error('Constructing \Drupal\search_api\Utility\FieldsHelper without the $themeSwitcher parameter is deprecated in search_api:8.x-1.31 and it will be required in search_api:2.0.0. See https://www.drupal.org/node/3320841',
+        E_USER_DEPRECATED);
+      $themeSwitcher = \Drupal::service('search_api.theme_switcher');
+    }
     $this->entityTypeManager = $entityTypeManager;
     $this->entityFieldManager = $entityFieldManager;
     $this->entityBundleInfo = $entityBundleInfo;