What happened: Marcus Mariota replaced Jayden Daniels under center to start the second half against the Dallas Cowboys. Daniels exited on the final play of the first half and was officially ruled out with a left elbow injury.

Why it matters: The injury mirrors a left elbow issue that previously cost Daniels four games. Mariota assumes control of the offense after missing the end of the preseason with an MCL sprain.

What to watch: Washington will conduct further evaluation on Daniels' elbow to determine his availability moving forward.