Siemian (sprained left foot) has been ruled out for Sunday's game against the Jaguars.
Siemian, who did not practice this week, will be replaced in the team's starting lineup by rookie Paxton Lynch; Austin Davis is set to serve as the backup. The Broncos' usual starter, who has been sporting a walking boot this week, will look to recover in time for a potential return to action in the Broncos' Week 14 road game against the Titans.