Why in the world was he even still on the roster ? Some more of pioli's ego and not wanting to admit mistakes and move on i reckon.
If he's as bad as you saw then they should in no way bring him back at all.
What other 3rd string QB do you want to hire just to sit on the bench as an emergency should your #1 and #2 get hurt in the same game. Had both Quinn and Cassel got hurt. The Chiefs would have gone out and picked up someone, just like they did last year with Orton to start.
Stanzi only saw active duty when one of the two QB's were hurt. After that the Emergency QB was a WR.