Wow. I am shocked by the response to moving Z to the bullpen. This move makes more and more sense to me the more I think about it.
Look at this this way, starting rotation, not a problem. Bullpen = horrible. Zambrano, imo, would have the best impact of all our starters coming out of the pen. Now, if he was pitching much better than the other starters, then yeah, you don't make the move. The way he has pitched though, mediocre, suggests to me that he is the perfect choice to make the move.
I don't see this as a demotion or reflection on him, as much as I see it as a reflection on the Bullpen. Something had to be done and he is the best suited to make the switch.
My formula:
Starting pitching - Zambrano + Lilly = same
Starting pitching - Silva or Gorzelanny + Lilly = right now maybe a tad better, but close.
Bullpen + Zambrano = decent chance to be significantly better
Bullpen + any other starter = not much different
This is all temporary until Silva or Tom G. implode and are done in the rotation, anyway. I am really starting to like this move.