Michalek, who had a career-best 35 goals last season, has been out since injuring his knee during pregame warm-ups prior to a game at the Pittsburgh Penguins on Feb. 13.
"I'm ready," Michalek said. "I practiced today and I'm excited for tomorrow."
The banged-up Senators have done well in Michalek's absence, going 5-3-2 -- they've scored 17 goals in that span (1.70 goals per game).
"With Milan we're getting someone that has the ability to put the puck in the net for us," Senators coach Paul MacLean said. "Milan has the history of it, and the expectation is he'll help the offense."