diff --git a/lib/middleman/features/asset_host.rb b/lib/middleman/features/asset_host.rb
index 4ac03506..342955ae 100644
--- a/lib/middleman/features/asset_host.rb
+++ b/lib/middleman/features/asset_host.rb
@@ -3,7 +3,7 @@ class Middleman::Base
     ::Compass.configuration do |config|
       config.asset_host(&self.asset_host)
     end
-  end if self.enabled?(:asset_host)
+  end if self.enabled?(:asset_host) && self.asset_host && self.asset_host.is_a?(Proc)
 end
 
 class << Middleman::Base
@@ -13,15 +13,11 @@ class << Middleman::Base
     
     valid_extensions = %w(.png .gif .jpg .jpeg .js .css)
     
-    if !self.enabled?(:asset_host) || path.include?("://") || !valid_extensions.include?(File.extname(path)) || !self.asset_host
+    if !self.enabled?(:asset_host) || path.include?("://") || !valid_extensions.include?(File.extname(path)) || !self.asset_host || !self.asset_host.is_a?(Proc) || !self.asset_host.respond_to?(:call)
       return original_output
     end
 
-    asset_prefix = if self.asset_host.is_a?(Proc) || self.asset_host.respond_to?(:call)
-      self.asset_host.call(original_output)
-    else
-      (self.asset_host =~ /%d/) ? self.asset_host % (original_output.hash % 4) : self.asset_host
-    end
+    asset_prefix = self.asset_host.call(original_output)
     
     return File.join(asset_prefix, original_output)
   end