From CBC’s Elliotte Friedman:
The NHL’s hockey operations department has modified how it will enforce the “jersey tuck” rule. If the sweater tucks while a player is skating, there will be no warning/penalty providing it was untucked at the beginning of a shift. That eases one of the bigger complaints, while allowing the league to pursue players who deliberately flout this crackdown.
Of course, this won’t make Alex Ovechkin any happier, as he’s always been an intentional tucker.
This is actually a thing now.