diff --git a/Library/Homebrew/cmd/doctor.rb b/Library/Homebrew/cmd/doctor.rb
index 1342f9a84fe7a4e1d6a3f2565ac28e077fe3e916..d4cd7f349a8651b23703c9a21fb961b0a6444f96 100644
--- a/Library/Homebrew/cmd/doctor.rb
+++ b/Library/Homebrew/cmd/doctor.rb
@@ -844,6 +844,7 @@ def check_for_bad_python_symlink
 end
 
 def check_for_outdated_homebrew
+  return unless which 'git'
   HOMEBREW_REPOSITORY.cd do
     if File.directory? ".git"
       local = `git rev-parse -q --verify refs/remotes/origin/master`.chomp