I mean, it was a pretty simple question - what's the difference between the 2C and 3C on the Devils in 2018? - but I guess I'll just answer it myself. There isn't a difference. They get around equal ice time, sometimes the Devils will use Zajac as a matchup guy, sometimes they won't. I don't think Johansson should go with Zajac, as I don't think their games mesh well together. So there is no difference. Obsessing over whether Zacha or Zajac should be the #2C doesn't make any sense.
The 2nd line isn't producing right now but they've gotten chances in the last 2 games.