Daniels was carted off the field at the conclusion of the first half due to a left arm injury, Tashan Reed of The Washington Post reports.
Daniels stumbled while taking the snap on the final play of the first half, and his left arm bent awkwardly while he was trying to catch himself from falling on the field. It's the same arm in which he suffered a dislocated elbow last season, and he's been carted to the locker room to undergo further tests. Assuming Daniels doesn't return, Marcus Mariota will take over under center for the Commanders, with rookie seventh-rounder Athan Kaliakmanis (coach's decision) serving as the team's emergency third quarterback.