The defenseman, who has six assists and is plus-7 in 32 games this season, was injured in the third period of a 3-2 overtime loss to the Montreal Canadiens on Wednesday.
"Maybe the most underrated player on our team," coach D.J. Smith said. "Certainly in the League. I don't think a lot of people realize how stable he is back there and just breaks up a lot of plays you just don't notice. But it will give a chance to somebody else."
Maxime Lajoie, who has no points in three games this season, will take his place in the lineup when the Senators (13-17-2) play the Columbus Blue Jackets (12-14-5) at Canadian Tire Centre on Saturday (1 p.m. ET; TVAS, SN, FS-O, NHL.TV).
"For the time being, [Lajoie] is going to get his opportunity, and that's kind of been the next-man-up mentality, if someone gets hurt, it's an opportunity to see another young guy," Smith said.
