According to the Ottawa Sun, the injury occurred during offseason training last month in Montreal.
Michalek, 27, is coming off the best season of his NHL career, when he set a career-high with 35 goals and totaled 60 points for just the second time in eight seasons. His 10 power-play goals also tied for the team lead.
Right now I'm just happy to be back and get through this season and make sure I do my job. I've never had an issue with having to prove myself again and I'll try to do it again. We'll see where it takes me.
— Defenseman Torey Krug on signing with the Boston Bruins