I still look at this recent decrease in IP as something the coaching staff caused unnecessarily with the move to the bullpen, and the management made worse with an overreaction. The performance is down as well, but the lack of IP is as much a Cubs problem as a Zambrano problem, if not more. That's largely true, but he hasn't been the picture of health, either. But given the circumstances (the non-chemistry/attitude ones), the hows and whys don't really matter. It was sunk cost, he wasn't putting the Cubs over the top in 2012 and he wasn't getting extended. There was nothing to be gained by keeping him and something (debate how much of a something that is if you will, but it was more than would be had by letting him walk) was gained by trading him. Like TT said, if Z were under contract for an additional year or two, Theo probably tries to hold on to him. But as it stood, that wouldn't have made much sense.