The New York Rangers probably should have taken a two-goal lead early in the second period, but ended up killing a penalty instead. With Rangers forward Chris Kreider racing into the Penguins zone, he was pushed from behind by Penguins defenseman Kris Letang and right into goaltender Marc-Andre Fleury. The puck went in the net, but the referee emphatically waved the goal off.
Kreider was whistled for goaltender interference. He unquestionably made contact with Fleury, but the question is whether or not Kreider made contact because he was pushed into Fleury.
It's not necessarily a simple call, but even at full speed it was pretty clear Letang made contact with Kreider, causing him to make contact with Fleury. If Kreider had any time at all to avoid contact with Fleury it was about a split-second's worth as he was moving at a high rate of speed.
As Rule 69.1 clearly states, in part:
If an attacking player has been pushed, shoved, or fouled by a defending player so as to cause him to come into contact with the goalkeeper, such contact will not be deemed contact initiated by the attacking player for purposes of this rule, provided the attacking player has made a reasonable effort to avoid such contact.
There is room for referee interpretation, of course.
Now you can say Kreider did not make a reasonable effort to avoid contact, but again, did he have a reasonable amount of time to avoid such contact? Probably not.
Here's a look at the GIF via @myregularface:
Here's where I think the referee has a case for making this call, however.
Kreider clearly loses his balance, but he steadies himself before making contact with Fleury. Kreider's arm is tucked similar to a position a player would make when delivering a body check. After making contact, Kreider's arm extends a bit, again similarly to a body check. That said, a reasonable argument could be made that Kreider was merely bracing for impact and his momentum carried him through.
It's one of those split-second decisions where tiny things can play a role into the referee's call. This one definitely toes the borderline, but it's not totally surprising to see it called.
The nature of goalie interference rules is to protect the goaltenders. Fleury took a pretty good whack there. As important as protecting goaltenders is, however, getting the call right is probably more important, especially in a potential elimination game.
The Rangers have a reasonable gripe that the game should have been 3-1 at that point. Lucky for New York, Derick Brassard scored later in the period to give the Rangers a two-goal advantage. If it holds, they'll forget this call was ever made, probably.