I believe it was actually your post that I responded to in another thread - maybe not, but look at the stats for Zaitsev over the past 2 seasons. He has the traditional stats (goals, assists, points, +/-, Gv away, tk away) and the advanced stats (corsi, fenwick, goal for per 60, goals against per 60, GAR, WAR) of a bottom pairing dman. His TOI is the only stat that puts him into the top 4 discussion. Now I'm not a stats only guy and I have watched Z play and he is solid in one on one battles, but his ability to drive the play is very poor, he has no outlet pass and offense drops off a cliff when he is one the ice. The high scoring Leafs had more goals against per 60 with Z on the ice than they did with him on the bench.
Whether its usage or ability is another discussion but by all tangible metrics he has not been a top 4 dman for 2 seasons.