The hit happened during the second period of Toronto's 4-3 shootout win Friday night. Kaberle made an uncontested pass in his own zone and was skating backward when Janssen checked him to the head about 3 seconds later. Kaberle fell and appeared to hit his head on the side boards.
"There's no correlation between Cam Janssen getting suspended three games and the Toronto Maple Leafs losing a key player like Tomas Kaberle at this time of year, especially after the trade deadline," Leafs general manager John Ferguson said before Saturday's game against Buffalo.
"It's as bad a hit that I've seen in a long, long time."
Kaberle was on the ice for several minutes and eventually was wheeled off after a neck brace was applied.
"We don't know how long (Kaberle will be out)," Ferguson said. "It's too early to tell."
Referees Kelly Sutherland and Brad Watson didn't call a penalty, and they refused to be interviewed after the game.
Janssen will miss New Jersey's games against Boston, Philadelphia and Pittsburgh and could return at Buffalo on March 10. He will forfeit $7,220.16 because of the suspension without pay.