从DB中保存的邮件中删除URL

I'm trying to remove URL from saved text in DB but first i want to save into variable for posting to facebook timeline..

unset($matches);

    preg_match_all('#\bhttps?://[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/))#',$post['message'],$matches);

    if (!empty($matches[0][0])) {
        $link = $matches[0][0];
        $params['link'] = $link;

        preg_replace($matches[0][0], '', $post['message']);
    }

        $link = '';

        $ret = $facebook->api('/'.$post['data1'].'/feed', 'POST', $params);

Basiclly im matching URL's then Im checking if there was any matches in $post['message] then save it into variable $link for facebook post.. but with that i want to delete all url matches from this post db.. i used:

preg_replace($matches[0][0], '', $post['message']);

but it doesn't work.. any ideas ?

Just use

str_replace($matches[0][0], '', $post['message']);