Manning is going to play against Washington, but he's going to be on pain killers. Dr. Robert Anderson confirmed that neither injury is severe, but ankle sprains can linger, and it's undoubtedly a concern for the team.
Manning originally sprained his ankles when the Broncos played the Jacksonville Jaguars, and he aggravated his right ankle sprain when they played the Indianapolis Colts.
While his mobility will be severely limited, he's strictly a pocket passer and he rarely gets out of the pocket anyway. However, the offensive line will need to step up in order to protect him. Knowshown Moreno will also likely stay in more to block out of the backfield.