To those suggesting substituting Perfetti and/or Namestnikov from the 2B line, may I suggest looking at that line as a shutdown line similar to the (2A) Lowry line .....and the problem goes away!!
PNE has allowed 6 goals against all season. Six! The Lowry line (NLA) has allowed 7 GA, while the Scheifele line (CSV) has allowed 24 GA. The difference really is, that the Scheifele line is high event (lots of goals for but also against), while the Namestnikov line is low event (less goals for but even fewer against). Both Namestnikov and Perfetti have excellent defensive awareness and positioning, and works well with Ehlers' oneman raids.
I am aware, they have primarily offensive zone starts (similar to the Scheifele line), while the opposite is true for the Lowry line, but with regards to playstyle they share the same ability to shutdown the opposition.
Be careful what you wish for! Instead of Namestnikov/Perfetti you may end up with defensively worse players.
Obviously, I would love more production from Perfetti/Namestnikov, but I am sure, Perfetti will learn to hit the goal instead of the absurd number of goal posts.