It's not a comparison so much as an archetype. Cosell is saying that if everything works out for Josh Rosen, if he trains on the way he needs to, and if the coaching staff can hold his hand enough, then you could see another Jared Goff.
What he doesn't say in there is that he considers Jared Goff to be a system quarterback that can only achieve great results in a very narrow set of circumstances.
I don’t see Any comparison in the arms....Rosen is far superior potentially in my opinion...what do you think?