Krebs was assessed a two-minute minor penalty for boarding on the play. For the nature of the reckless hit, he's lucky it wasn't a major penalty and game misconduct. However, he may have to answer directly to Pezzetta for the hit later in the game.
It's unlikely the league's department of player safety takes a look at this hit from the fact it was only a minor penalty, and realistically, isn't the most of egregious or forceful hits from behind.