diff --git a/lib/jekyll/frontmatter_defaults.rb b/lib/jekyll/frontmatter_defaults.rb
index be749384..a9a02f5a 100644
--- a/lib/jekyll/frontmatter_defaults.rb
+++ b/lib/jekyll/frontmatter_defaults.rb
@@ -207,11 +207,14 @@ module Jekyll
     end
 
     # Sanitizes the given path by removing a leading and adding a trailing slash
+
+    SANITIZATION_REGEX = %r!\A/|(?<=[^/])\z!
+
     def sanitize_path(path)
       if path.nil? || path.empty?
         ""
       else
-        path.gsub(%r!\A/|(?<=[^/])\z!, "".freeze)
+        path.gsub(SANITIZATION_REGEX, "")
       end
     end
   end