diff --git a/wp-includes/post-thumbnail-template.php b/wp-includes/post-thumbnail-template.php
index 4722565d96..0dbe74aad6 100644
--- a/wp-includes/post-thumbnail-template.php
+++ b/wp-includes/post-thumbnail-template.php
@@ -122,11 +122,13 @@ function get_the_post_thumbnail( $post = null, $size = 'post-thumbnail', $attr =
 	 * Filters the post thumbnail size.
 	 *
 	 * @since 2.9.0
+	 * @since 4.9.0 Added the `$post_id` parameter.
 	 *
-	 * @param string|array $size The post thumbnail size. Image size or array of width and height
-	 *                           values (in that order). Default 'post-thumbnail'.
+	 * @param string|array $size    The post thumbnail size. Image size or array of width and height
+	 *                              values (in that order). Default 'post-thumbnail'.
+	 * @param int          $post_id The post ID.
 	 */
-	$size = apply_filters( 'post_thumbnail_size', $size );
+	$size = apply_filters( 'post_thumbnail_size', $size, $post->ID );
 
 	if ( $post_thumbnail_id ) {
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index fc4a455232..077cfe8dee 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.9-alpha-41266';
+$wp_version = '4.9-alpha-41267';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.