Penguins' Mike Matheson: Officially moves to IR

Matheson (upper body) was placed on injured reserve Sunday, Seth Rorabaugh of TribLive.com reports.

Head coach Mike Sullivan said Sunday that Matheson will be out "longer term" but didn't provide the nature of the defenseman's injury. Due to his placement on IR, Matheson will miss at least a week, and it sounds like he'll miss further time, too. Juuso Riikola slotted into the lineup in Matheson's place Sunday and could handle the third-pairing role moving forward.