Michalek has played in two games since Feb. 12. He tried to return and play through the injury, recording assists against the Toronto Maple Leafs on March 6 and the New York Rangers on March 8, but hasn't been in the lineup since.
In 15 games this season, Michalek has two goals and 10 points. He led the Senators with 35 goals last season and was third with 60 points.
The Senators' top-two scorers from last season, forward Jason Spezza and defenseman Erik Karlsson, also have been out of the lineup with long-term injuries.
I'm here to develop a winning culture and a winning team. There is a bright future ahead of this team. A lot of young, great hockey players here and on the way … a fan base that's passionate about the game of hockey.
— Dan Bylsma after being introduced as new coach of the Buffalo Sabres