Both players have been battling it out since the start of training camp.
Joseph also announced that Lynch will start the team's second preseason game, next Saturday in San Francisco.
Coach Vance Joseph announced after Monday's indoor practice that Siemian will get first crack against the Bears on Thursday night while Lynch will start Denver's second game, at San Francisco on August 19.
The preseason will be an opportunity for one of Siemian or Lynch to create some distance over the other in the race to be Denver's starter.
This was a similar situation a year ago. If Lynch comes up short again against Siemian for a second year, the there might be another problem for the Broncos. On top of that, Lynch was a highly regarded first-rounder, while Siemian was a nobody seventh-round pick who would have been undrafted if not for the fact that Gary Kubiak took a liking to him coming out of Northwestern in 2015. He made the correct reads most of the time. "I think Trevor's earned that much". If he doesn't win the starting job, don't be surprised if the Broncos go look for another quarterback in the future. At that point, the Broncos would likely want their starter getting the majority of reps with the first team.