However, some hairs stand up on end (the Russian bear) when a NATO power gets close to Ukraine.
i am sure that Russia won`t complaint if Poland solely (not as part of NATO) gets close to Ukraine. Throughout history Russia only profited from existence of Slavic states on her western borders. Now, Russia for sure understand processes of globalization and facts that Slavs on her western borders (from Baltic to Balkan) needs to join efforts if wants to survive. So, Russia won`t complaint if influence of Poland expand. Trust to this info, when Serbian inform you.
For many reasons Russia can`t directly intervene to support (even if wants that) western or southern Slavs but, Poland can for many reasons. Strengthening of Slavic element on Balkan-Baltic line generally suits to Russian interests (better Slavs on her western borders then Germanics and/or Turks).
So, if Poland represent that key to the strengthening of Slavs on Balkan-Baltic line, even if it mean lesser Russian control over those Slavs, Russia would even support Polish intention to strengthen.
Russia is today, more then ever, natural ally of Poland.