Booker
All-Pro
Online
For what it's worth, Haener is listed second team on the team website, so at least for now it looks like he'd be the first man up. And I think your rationale is correct, in that Rattler isn't ready for that responsibility yet.If a backup QB has to be announced, I think it will be Haener as he is more "seasoned" than Rattler as to give Rattler more time to get accustomed to being a professional week in and week out.
But at the same time, what seasoning does Haener really have, and between the two, does a year carrying a clipboard on gameday and running the scout team really make up for him only being able to make a fraction of the throws that Rattler can make?
I haven't seen anything from Haener that has suggested there's anything special about him, and wouldn't be opposed to letting him go in favor of a veteran backup, with Rattler filling the project/prospect role that Haener filled last year. But Carr has also been a pretty durable quarterback throughout his career, so maybe the whole backup question is moot.