Remove related posts from its default position and change the headline.

tps-change-jetpack-related-posts.php

<?php
/*
 * Remove Jetpack related posts
 * Description: Add the functions and filters below to your funcions.php to remove related posts from its default position and change the headline
 * Author: Tatiane Pires
 * Author URI: http://tatianepires.com.br
 * Version: 1.0
 */
 
/*
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

/*
 * Remove Related Posts from the default position
 * It will be added in the right place with a shortcode on single.php
 */
function tps_remove_jetpack_related_posts() {
    if ( class_exists( 'Jetpack_RelatedPosts' ) ) {
        $jprp = Jetpack_RelatedPosts::init();
        $callback = array( $jprp, 'filter_add_target_to_dom' );
        remove_filter( 'the_content', $callback, 40 );
    }
}
add_filter( 'wp', 'tps_remove_jetpack_related_posts', 20 );

/*
 * Optional
 * Change the headline
 */
function tps_change_jetpack_related_posts_headline( $headline ) {
  $headline = sprintf(
              '<strong class="related-posts-title">%s</strong>',
              esc_html( 'Posts relacionados' )
              );
  return $headline;
}
add_filter( 'jetpack_relatedposts_filter_headline', 'tps_change_jetpack_related_posts_headline' );

/*
 * Line to add on single.php:
 * if ( class_exists( 'Jetpack_RelatedPosts' ) ) echo do_shortcode( '[jetpack-related-posts]' );
 */

/*
 * Reference: https://jetpack.com/support/related-posts/customize-related-posts/
 */
?>