For the first time in four years the world champion Denver Broncos take to the field not knowing who is the teams first string quarterback. The off-season battle for that position became a bit clearer this week after the Broncos revealed that Mark Sanchez will be the starting quarterback in the preseason opener Thursday when the Broncos face the Bears in Chicago. Sanchez will play the first quarter with Trevor Siemian taking over in the second quarter. The second half will be owned by the rookie Paxton Lynch. Again this year 55 Country (AM 550), the official Denver Broncos station for Northwest Colorado, will broadcast the Broncos games across the region. Catch tomorrows preseason opener beginning with our pregame at 4:05. Kickoff will be at 6.