Chaisson suffered a knee injury in last week's joint practice with the Dolphins, Tashan Reed of The Washington Post reports.
Chaisson did not participate in Tuesday's practice due to the injury. With Jer'Zhan Newton (pec) and Odafe Oweh (calf) also sustaining injuries, the Commanders' defensive line looks like it has taken a huge step back just one week into the preseason. Chaisson's return timeline is unclear, and the team will likely look to add a depth pass rusher in free agency ahead of Saturday's preseason game against the Lions.