Filters The SEO Framework's excerpt and replaces it with "excerpt_description" created via Advanced Custom Fields.

tsf-acf-filter-excerpt.php

<?php
// Don't include the PHP opening tag if PHP is already open.


add_filter( 'the_seo_framework_get_excerpt', 'my_tsf_acf_excerpt', 10, 2 );
/**
 * @param string     $excerpt The obtained excerpt.
 * @param array|null $args    The query arguments. Contains 'id', 'tax', 'pta', and 'uid'.
 *                            Is null when the query is auto-determined.
 * @return string The overwritten description.
 */
function my_tsf_acf_excerpt( $excerpt, $args ) {

	// If ACF isn't activated, don't do anything.
	if ( ! function_exists( 'get_field' ) ) return $excerpt;

	if ( isset( $args ) ) {
		// Admin area.
		if ( 'single' === The_SEO_Framework\get_query_type_from_args( $args ) ) {
			$post_id = $args['id'];
		}
	} else {
		// On the front-end.
		$tsfquery = tsf()->query();

		if ( $tsfquery->is_singular() ) {
			$post_id = $tsfquery->get_the_real_id();
		}
	}

	if ( ! empty( $post_id ) )
		$excerpt = get_field( 'excerpt_description', $post_id ) ?: $excerpt;

	return $excerpt;
}