I don't really agree with much of this. Zambrano, if he continues to pitch well for the rest of the season, could end up as the No. 3 starter -- behind Dempster and Gorzo. It's been debated around here, but I think the Cubs are better off rolling the dice with Z than taking on another team's problem child (e.g. Oliver Perez). Anyway, if the Cubs trade anybody to dump salary, they'll trade Fukudome to open a spot for Colvin. At least, that's what I would do.
Meanwhile, I also don't see Wells and Silva as sure bets. Wells is no more than a decent No. 4 starter and I bet Silva ends up in the bullpen because of his conditioning/health issues.
If Z somehow returns to old form and finally grows up ... it could be one key to fringe contention for the Cubs in 2011.