Starter: Drew Lock
Backup: Jeff Driskel
Outside looking in: Riley Neal (practice squad), Brett Rypien (cut)
We can say it is safe to assume that Drew Lock and Jeff Driskel are locked in to make the final roster. As for the 3rd quarterback, the Broncos may decide to stash either Brett Rypien or Riley Neal on the practice squad.
The Broncos may find value in Rypien or Neal as a developmental quarterback, but neither displays the tools warranting a roster spot and a street free agent could be picked up to provide something similar during the season.
Final prediction: The Broncos roll with Lock and Driskel and stash Neal on the practice squad. Rypien finds a team running a “Shannahan” style west coast system as a 3rd option.