diff --git a/lib/jekyll/draft.rb b/lib/jekyll/draft.rb
index 27f9d2a1..16daefdf 100644
--- a/lib/jekyll/draft.rb
+++ b/lib/jekyll/draft.rb
@@ -14,8 +14,8 @@ module Jekyll
     end
 
     # Get the full path to the directory containing the draft files
-    def containing_dir(source, dir)
-      Jekyll.sanitized_path(source, File.join(dir, '_drafts'))
+    def containing_dir(dir)
+      site.in_source_dir(dir, '_drafts')
     end
 
     # The path to the draft source file, relative to the site source
diff --git a/lib/jekyll/post.rb b/lib/jekyll/post.rb
index 36536173..861ba4ca 100644
--- a/lib/jekyll/post.rb
+++ b/lib/jekyll/post.rb
@@ -49,7 +49,7 @@ module Jekyll
     def initialize(site, source, dir, name)
       @site = site
       @dir = dir
-      @base = containing_dir(source, dir)
+      @base = containing_dir(dir)
       @name = name
 
       self.categories = dir.downcase.split('/').reject { |x| x.empty? }
@@ -88,8 +88,8 @@ module Jekyll
     end
 
     # Get the full path to the directory containing the post files
-    def containing_dir(source, dir)
-      return File.join(source, dir, '_posts')
+    def containing_dir(dir)
+      site.in_source_dir(dir, '_posts')
     end
 
     # Read the YAML frontmatter.