Matthews (upper body) was a partial participant in Monday's practice session but has been ruled out for Tuesday's game against the Islanders, Dave McCarthy of NHL.com reports.
Matthews has been sidelined since sustaining an upper-body injury against Buffalo on Dec. 20, but he's been getting some ice time during practice in recent days. While he'll be unavailable for a fifth consecutive game Tuesday, he appears to be trending in the right direction. His next opportunity to return will be Thursday in a rematch against the Islanders.