diff --git a/lib/jekyll/document.rb b/lib/jekyll/document.rb
index fecd5828..386683d6 100644
--- a/lib/jekyll/document.rb
+++ b/lib/jekyll/document.rb
@@ -9,7 +9,7 @@ module Jekyll
 
     YAML_FRONT_MATTER_REGEXP = %r!\A(---\s*\n.*?\n?)^((---|\.\.\.)\s*$\n?)!m
     DATELESS_FILENAME_MATCHER = %r!^(?:.+/)*(.*)(\.[^.]+)$!
-    DATE_FILENAME_MATCHER = %r!^(?:.+/)*(\d{4}-\d{2}-\d{2})-(.*)(\.[^.]+)$!
+    DATE_FILENAME_MATCHER = %r!^(?:.+/)*(\d{2,4}-\d{1,2}-\d{1,2})-(.*)(\.[^.]+)$!
 
     # Create a new Document.
     #