IMHO, we've seen what Masoli can do, or not do, over the last number of games. Without giving anyone the idea I've given up on the season, I would like to see what Zach can do given what seems to be an improved O-line, improved/returning players and starters, and simplified playbook.
Today's article in The Spec indicates coach Jones will not make a QB change, he being relatively happy with Masoli's play so far. Personally, I've been disappointed in Masoli's passing inconsistency and poor time/clock management (ie, often slow and lackadaisical breaking the huddle and starting the play).
Start Collaros and see what he can do. It seems the team has given up on him as it is.