From the great Chris Johnston:
There will be no discipline hearing for Torey Krug following his hit on Andrew Shaw last night.— Chris Johnston (@reporterchris) December 13, 2016
I think the league made the right call here. Krug was committed to the hit before Shaw ducked, and really couldn't do much to avoid the hit other than simply let Shaw go by.
Also, Krug didn't really drive upward through the head. Helping Krug's cause was the fact that Shaw returned to the game.
In any case, Krug is a free man.
EDIT (10:53 AM): More info from Johnston:
Feeling is that Shaw put himself in a vulnerable position. Made head contact unavoidable on what otherwise would have been a full bodycheck.— Chris Johnston (@reporterchris) December 13, 2016