What happened: Mattias Samuelsson is out week to week with a lower-body issue. Olen Zellweger has entered concussion protocol, according to head coach Lindy Ruff.

Why it matters: The dual absences disrupt the defensive rotation for Buffalo midway through the exhibition slate. The coaching staff views the situation as an opportunity for depth players to log additional minutes before the regular season begins.

What to watch: Zellweger must clear all mandated steps of the league protocol before returning to the ice.