[qwerty49]

Mills's opponent-adjusted PER:154.7, 24th in the country.

Costello's: 108.6; 121st.

Seems like we have a choice-of-quarterback's problem.

I would agree with you if Mills could stay healthy.
Unfortunately, he can't.

Mills may appear to be more effective at this point, but Shaw and Bruce Bochy value seniority very highly.  There must be exceptions, maybe starting Kelly over Eboh is one.

[qwerty49]

Mills's opponent-adjusted PER:154.7, 24th in the country.

Costello's: 108.6; 121st.

Seems like we have a choice-of-quarterback's problem.

I would agree with you if Mills could stay healthy.
Unfortunately, he can't.

Mills may appear to be more effective at this point, but Shaw and Bruce Bochy value seniority very highly.  There must be exceptions, maybe starting Kelly over Eboh is one.