If his confidence dwindled or he got banged up, a look at Chase wouldn't hurt anyone for a breather...like if it gets bad with 0-3 or 0-4 start...I'd be fine with Chase week 5 before the bye and regroup.
Chase will disappoint alot of people though, his mobility is zero, his panic is high, his height is low, and he throws loopy passes. There are defenses he can't beat, and there are defenses this offense matches up to he could steer the ship, imo.
Trubisky is doing fine, he isn't Glennon bad or anything. He is right in that 15-25 range of QB's, where 3300, 400, 25/12 says you are. He is that and improving incrementally. Even matching that against a rough schedule would be improvement.
He is young and inexperienced, but a better athlete than most of us realized even looking at his 4.67. Sturdy little chap, wide rib cage, decent arm and a hard worker.