Display Post Author Link above the loop

It make use of global variable $post to get author id of current post. Using that this function returns the author url.

Note –

Make sure you put this in condition ( is_single() ) so it only print author url on single.php.

<?php echo get_author_posts_url( $post->post_author ); ?>

Update –

<?php $username = get_userdata( $post->post_author ); ?>    
<a href="https://wordpress.stackexchange.com/questions/61367/<?php echo get_author_posts_url( $post->post_author ); ?>"><?php echo $username->user_nicename; ?></a>

^{This will work, but I’ll update my answer if I found more efficient method.}