diff --git a/lib/faraday/connection.rb b/lib/faraday/connection.rb
index ae0eb7da1..65ba8cbe8 100644
--- a/lib/faraday/connection.rb
+++ b/lib/faraday/connection.rb
@@ -73,6 +73,7 @@ def initialize(url = nil, options = nil)
       @options = options.request
       @ssl = options.ssl
       @default_parallel_manager = options.parallel_manager
+      @manual_proxy = nil
 
       @builder = options.builder || begin
         # pass an empty block to Builder so it doesn't assume default middleware