Index: wp-includes/link-template.php
===================================================================
--- wp-includes/link-template.php	(revision 18679)
+++ wp-includes/link-template.php	(working copy)
@@ -1456,27 +1456,29 @@
 	else
 		$post = get_adjacent_post($in_same_cat, $excluded_categories, $previous);
 
-	if ( !$post )
-		return;
+	if ( !$post ) {
+		$output = '';
+	} else {
 
-	$title = $post->post_title;
+		$title = $post->post_title;
 
-	if ( empty($post->post_title) )
-		$title = $previous ? __('Previous Post') : __('Next Post');
+		if ( empty($post->post_title) )
+			$title = $previous ? __('Previous Post') : __('Next Post');
 
-	$title = apply_filters('the_title', $title, $post->ID);
-	$date = mysql2date(get_option('date_format'), $post->post_date);
-	$rel = $previous ? 'prev' : 'next';
+		$title = apply_filters('the_title', $title, $post->ID);
+		$date = mysql2date(get_option('date_format'), $post->post_date);
+		$rel = $previous ? 'prev' : 'next';
 
-	$string = '<a href="'.get_permalink($post).'" rel="'.$rel.'">';
-	$link = str_replace('%title', $title, $link);
-	$link = str_replace('%date', $date, $link);
-	$link = $string . $link . '</a>';
+		$string = '<a href="'.get_permalink($post).'" rel="'.$rel.'">';
+		$inlink = str_replace('%title', $title, $link);
+		$inlink = str_replace('%date', $date, $inlink);
+		$inlink = $string . $inlink . '</a>';
 
-	$format = str_replace('%link', $link, $format);
-
+		$output = str_replace('%link', $inlink, $format);
+	}
+	
 	$adjacent = $previous ? 'previous' : 'next';
-	echo apply_filters( "{$adjacent}_post_link", $format, $link );
+	echo apply_filters( "{$adjacent}_post_link", $output, $format, $link );
 }
 
 /**