diff --git a/wp-admin/includes/upgrade.php b/wp-admin/includes/upgrade.php
index 98c015ea0a..48cd7be662 100644
--- a/wp-admin/includes/upgrade.php
+++ b/wp-admin/includes/upgrade.php
@@ -2457,11 +2457,6 @@ function pre_schema_upgrade() {
 		}
 	}
 
-	if ( $wp_current_db_version < 30133 ) {
-		// dbDelta() can recreate but can't drop the index.
-		$wpdb->query( "ALTER TABLE $wpdb->terms DROP INDEX slug" );
-	}
-
 	// Upgrade versions prior to 4.2.
 	if ( $wp_current_db_version < 31351 ) {
 		if ( ! is_multisite() ) {