Lock, who's yet to debut in the regular season, has taken most of the first-string reps in practice this week ahead of Brandon Allen.
The second-round pick suffered a thumb injury during the preseason and has been brought along slowly since returning to practice two weeks ago.
Lock struggled in limited preseason action, which led Broncos head coach Vic Fangio to admit the rookie wasn't close to earning the starting spot. However, Fangio noted Lock's improvement over the last couple of weeks.
Allen started Denver's last three games after veteran Joe Flacco landed on injured reserve, going 1-2.