I think Rattler got the start while Carr was out because he was more mobile than Haener and our O-line was decimated at the time. In college, Rattler could move around and buy time in the pocket but he wasn’t ready for the speed of the NFL.
When Haener has come in, he’s shown very good poise in the pocket, the ability to go through reads, and get the ball out quick. I’m in no way saying Haener will come in and look like Drew Brees, but he does deserve a chance with the starting offense to show if he has what it takes or not.
Allowing Haener to start will give both he and Rattler some game film for who ever is HC & OC to evaluate and determine if they want to go after a QB in the draft or not.