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 remember the first time at Wrigley Field all of us had the long johns, the turtlenecks and the extra equipment because we were afraid of being cold. Halfway through the first period everybody's ripping everything off and we just ended up wearing what we would normally wear for a game at the United Center.
— Chicago Blackhawks forward Patrick Sharp on the 2009 Bridgestone NHL Winter Classic