[Jewpac]

The definition of boarding:

Boarding
Boarding occurs when a player is facing the boards and an opposing player checks him from behind so that he is violently crushed into the boards. A player can be assessed either a minor or major penalty for boarding, and in many cases more severe penalties or suspensions will be assessed, because players can be very badly hurt from this. If a player is bent over and is slammed into the boards, he can suffer a concussion or even a broken neck, so players and officials alike frown heavily upon players who commit boarding.

Explain to me how the hit on Marleau by Phaneuf does not meet that definition.