this is pretty simple: if you are good, you get several opprotunities, if you aren't, you don't. zambrano has been good, but he is not quite so this year. so while he has "gotten away with it" before and been ok, this isn't like when bradley had actually been producing when he was given away, zambrano has a WHIP of 1.44 and an ERA of 4.82. what's more is his homerun rate has more than doubled, his strikeout rate has gone down, he is giving up more than a hit per 9 more than last year, and, obviously his ERA+ is down, but it is -40 from last season. his FIP is right in line with his baseball card stats, all while having a BABIP against that is a mere .003 lower than last year. i'm sorry, but that he has been good does not get a pass. is he replaceable? his current version is easily done so, yes. and though people are throwing casey coleman and others around, really, they wouldn't be much worse, if any. you could argue that zambrano has shown ability to be much more, but you could also argue that some of the AAAA guys have more of a ceiling at this point. whether he has been good means little in whether he should be retained in light of who he has been recently and who he likely is going to be going to forward, all other things considered.