diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 0743c6e031..1c74d9a0c3 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -1226,28 +1226,27 @@ module Homebrew
 
       def check_for_outdated_homebrew
         return unless Utils.git_available?
-        HOMEBREW_REPOSITORY.cd do
-          if File.directory? ".git"
+
+        timestamp = if File.directory?("#{HOMEBREW_REPOSITORY}/.git")
+          HOMEBREW_REPOSITORY.cd { `git log -1 --format="%ct" HEAD`.to_i }
+        else
+          HOMEBREW_LIBRARY.mtime.to_i
+        end
+        return if Time.now.to_i - timestamp <= 60 * 60 * 24 # 24 hours
+
+        if File.directory?("#{HOMEBREW_REPOSITORY}/.git")
+          HOMEBREW_REPOSITORY.cd do
             local = `git rev-parse -q --verify refs/remotes/origin/master`.chomp
             remote = /^([a-f0-9]{40})/.match(`git ls-remote origin refs/heads/master 2>/dev/null`)
-            if remote.nil? || local == remote[0]
-              return
-            end
+            return if remote.nil? || local == remote[0]
           end
+        end
 
-          timestamp = if File.directory? ".git"
-            `git log -1 --format="%ct" HEAD`.to_i
-          else
-            HOMEBREW_LIBRARY.mtime.to_i
-          end
-
-          if Time.now.to_i - timestamp > 60 * 60 * 24 then <<-EOS.undent
+        <<-EOS.undent
           Your Homebrew is outdated.
           You haven't updated for at least 24 hours. This is a long time in brewland!
           To update Homebrew, run `brew update`.
-          EOS
-          end
-        end
+        EOS
       end
 
       def check_for_unlinked_but_not_keg_only