There is no reason to keep Zimmer past today. It isn't just about Zimmer, it's about the ownership telling the team that they won't accept the effort and suckage that they've displayed so far, and that the ownership wants to win. Let Malouf or Patterson finish out the year as Head Coach.
They can't just let it ride to a 2-14 or 1-15 season and expect people to continue tuning in, or to want to come back next year. Fire Zimmer and maybe even Spielman now, and use the rest of the season to get a head start on locating a new Coach and maybe a new GM.