Thumbnails in sidebar

I am trying to get the title of each post below the thumbnails in my sidebar.

The code I am currently using is

<div class="th fl"><?php
  $thumbnails = get_posts('numberposts=4');
  foreach ($thumbnails as $thumbnail) {
    if ( has_post_thumbnail($thumbnail->ID)) {
      echo '<a href="' . get_permalink( $thumbnail->ID ) . '" title="' . esc_attr( $thumbnail->post_title ) . '">';
      echo get_the_post_thumbnail($thumbnail->ID, 'thumbnail');
      echo '</a>';
    }
  }
?>

</div>

This draws the thumbnails into the sidebar but I cannot seem to be able to get the post titles below these.

Can someone please help.