Not realy an ACF question. Aber vielleicht:
$terms = array('1-herren');
$abfrage = array(
'post_type' => 'spieler',
'tax_query' => array(
array(
'taxonomy' => 'manschaft',
'field' => 'slug',
'terms' => $terms,
),
),
);
https://codex.wordpress.org/Class_Reference/WP_Query#Taxonomy_Parameters
