Savard sent a shot on the Pittsburgh net from a few feet inside the blue line with about six minutes remaining. A couple beats after he released it, Cooke came through with what looked on replays was either an elbow or shoulder that crumpled Savard.
Savard lost consciousness briefly and suffered a concussion from the hit, according to Bruins spokesman Matt Chmura.
No penalty was called on the hit and Pens went on to win the game, 2-1.
"After looking at the replay, it certainly doesn't look like a very good hit," said Boston coach Claude Julien in an interview on NESN after the game. "Hopefully the league will take care of it and make the right decision."
Julien said he expected Savard to be out "for a while," according to the Boston Globe.
The NHL has taken a tougher stance toward hits to the head and has imposed several fines and suspensions, even if if a penalty wasn't called on the ice.
Jack Edwards, the Bruins' play-by-play announcer, said Cooke "was trying to separate (Savard) from consciousness."