Wordpress: Updates a post type's slug and allows it to work with a custom segment.

update-post-type-slug.php

<?php 

/**
 * Updates the url to events plugin posts and adds new url rule to allow a string before the slug
 */
add_action('init', function(){
	$args = get_post_type_object("eventbrite_events");
	
	$args->rewrite["slug"] = "events/%organizer_name%";
	register_post_type($args->name, $args);

	add_rewrite_rule('events/(.+?)/(.+?)$', 'index.php?post_type=eventbrite_events&nothing=$matches[1]&name=$matches[2]', 'top');

});


/**
 * [$id description]
 * @var integer
 */
add_filter('post_type_link', function($post_link, $id = 0, $leavename = FALSE) {

  if (strpos('%organizer_name%', $post_link) === FALSE) {
    $post = get_post($id);
    
    if(!$post){
    	return str_replace('%organizer_name%', 'default', $post_link);
    }
    $category = get_post_meta($post->ID, 'organizer_name', true);
    $category = str_ireplace('ecreators', '', $category);
    $category = sanitize_title_with_dashes($category);

    return str_replace('%organizer_name%', $category, $post_link);
  }

}, 1, 3);