Matt Duchene scored a goal that was JUST a bit offside…

Barry Trotz said after the game, “The league already verified that it should have been an offside.”

It should’ve.  But here’s a possible reason – absent any actual explanation from the on-ice officials – that veteran linesman Derek Amell (#75) may have seen this one differently:

83.1 Off-side – Players of the attacking team must not precede the puck into the attacking zone.

 

… 

If a player legally carries or passes the puck back into his own defending zone while a player of the opposing team is in such defending zone, the off-side shall be ignored and play permitted to continue.

That section might create a little grey area.  The puck did appear to deflect off a Nashville player, though it wasn’t truly a back pass. Former referee Kerry Fraser agrees in his TSN column:  

A long stretch pass was intended for Colorado forward Matt Duchene as he snuck behind the Nashville defencemen. Scott Hannan’s desperation attempt to bat the puck down caused a redirection of the puck which then further deflected off the skate of Craig Smith. In both cases, this form of contact with the puck did not constitute possession or control by either of the two Nashville players. It would be no different had the puck been deflected off the shin guard or body of Hannan, followed by the skate of Smith which delayed the puck from crossing their blue line ahead of Matt Duchene. Off-side is the call!

So does TSN’s Bob McKenzie:

Even Duchene later admitted it. “I was 100% offside but, I think what the ruling was, was that Nashville brought the puck back in. So then, because they controlled it and brought it back, that it wasn’t offside,” said Duchene after the game. The Avs went on to win the game 6-5, so, yeah, that was a pretty important goal right there.