You need to add the meta_compare argument to the meta query . Now your code will be like :
'meta_query' => array(
'relation' => 'OR',
array(
'key' => 'pb_responsible_home_person',
'value' => $current_player_name,
'compare' => '='
),
array(
'key' => 'pb_responsible_away_person',
'value' => $current_player_name,
'compare' => '='
),
)// meta query end
EDIT
$current_player_name = get_post_meta( get_the_ID(), ‘football_team_team_name’, true );
$m_keys =array('pb_responsible_home_person','pb_responsible_away_person')
$meta_query = array('relation' => 'OR');
foreach ($m_keys as $m_key) {
$meta_query[] = array(
'key' => $m_key,
'value' => $current_player_name,
'compare' => '='
);
}
$args = array(
'post_type' => 'football_fixture',
'meta_query' => $meta_query
);
Try this, working when i checked locally