diff --git a/lib/sidekiq/core_ext.rb b/lib/sidekiq/core_ext.rb
index 932cfc9a..27d92267 100644
--- a/lib/sidekiq/core_ext.rb
+++ b/lib/sidekiq/core_ext.rb
@@ -90,7 +90,7 @@ end
 
 begin
   require 'active_support/core_ext/string/inflections'
-rescue LoadError
+rescue LoadError, NameError # NameError is necessary to run Sidekiq unofficially on Rails 2.3
   class String
     def constantize
       names = self.split('::')