Frycer14 said:
I'll solve this - you're both wrong (and right).
1) Matthews is stationary on the bench. Willy is already skating towards it. Just because Matthews might a couple feet closer to the play doesn't mean he could accelerate to make up the speed difference of Willy committing to a backcheck instead of the bench.
But there are two considerations for a player like Nylander in that situation. One is who is better suited to defend the ongoing play. I think that's Matthews in this case, you're free to think otherwise but I think you'd grant that at the very least it's close.
The second consideration though is who is better suited to be on the ice after whatever might happen on that one rush and the answer there is unquestionably a fresh Matthews instead of a tired Nylander.
Like you say, the goal rendered it moot and there's no real reason to assign blame but for me, in that situation, I'd want the defensive player to make the change.