When Michel Therrien mentioned the words "upper-body injury" during the post game press conference on Sunday, it was clear that Erik Karlsson's hit had taken its toll on Nathan Beaulieu.
Today, the Canadiens confirmed that their young mobile defensemen will indeed miss the rest of the series
#Habs just advised that Nathan Beaulieu will be out for the remainder of the series against the #Senators (upper body injury).— John Lu (@JohnLuTSNMtl) April 21, 2015
There's been much debate as to whether or not Karlsson's hit should be considered a headshot, although Therrien stated himself that it was legal.
Former referee Kerry Fraser elaborated further in this post.
As defined in Rule 48, Karlsson made an attempt to hit Beaulieu squarely through the body with a straight-on approach (Not angled). Beaulieu had just received the pass and put himself in a vulnerable position with head down and a lowered, forward leaning body posture that made head contact on an otherwise full body check unavoidable. (Beaulieu exposed his head as almost the leading edge of any impending contact.) Karlsson stiffened his posture at impact but still maintained some bend at his waist with skates on the ice. There was also very little gap space and time once Karlsson stepped up and committed to deliver the check. The circumstances of this play fall within the acceptable guidelines of rule 48 to deem it a legal check.
It remains to be seen who will replace Beaulieu in the lineup. Therrien can either use the experienced Sergei Gonchar, or he could turn to the more physical presence that is Greg Pateryn.
Update: Well, so much for mystery! It seems as if Pateryn is indeed the player who will slot into the lineup
Pateryn replaces Beaulieu on #Habs blue line. Pairings are Markov - Subban; Gilbert - Petry; Emelin - Pateryn.— John Lu (@JohnLuTSNMtl) April 21, 2015